TakeruK

(emphasis added)
To me, this is a description of one of the ways gender discrimination is indeed happening in STEM settings. We (well, the people in power) get to decide how STEM settings work and the choice to organize them in ways that favour traditionally masculine qualities is one of the ways discrimination manifests itself. And when the field (especially the group of people in power, which are often more senior) is over-represented in one gender, it creates possibilites for that gender to choose to favour traits that they have themselves instead of valuing diversity/differences.

(emphasis added)
To me, this is a description of one of the ways gender discrimination is indeed happening in STEM settings. We (well, the people in power) get to decide how STEM settings work and the choice to organize them in ways that favour traditionally masculine qualities is one of the ways discrimination manifests itself. And when the field (especially the group of people in power, which are often more senior) is over-represented in one gender, it creates possibilites for that gender to choose to favour traits that they have themselves instead of valuing diversity/differences.

I applaud you for sketching a budget prior to committing to housing!
It's simple to calculate your tax liability using the info you provided, at least for your first full year of employment (2019). 2018 may be different as you'll be starting/changing jobs mid-year.
For federal income tax, if you are single and take the standard deduction of $12,000, you will pay 0% tax on that first $12,000 of income, 10% tax on the next $9,525, and 12% on the remainder (these are the 2018 brackets). Using the numbers you provided, that is 10%*$9525+12%*($14,000-$9,525)=$1,489.50 or $124.13/mo.
This tax liability may shift if you have other adjustments to your income, such as additional income sources or above-the-line deductions, e.g., interest paid on student loans. You should check if you're receiving any scholarship funding or similar that isn't tax-free (i.e., money that goes toward fees that are not qualified education expenses) or if any of your stipend will go toward paying qualified education expenses. For estimation purposes, you could just add any net scholarship income to your stipend or subtract any net qualified education expenses from your stipend, even if that's not exactly how you'll treat it on your tax return. Check your offer letter for these kinds of details on your non-stipend funding.
You won't pay FICA tax no matter your funding source.
Tennessee doesn't have state income tax on ordinary income, just investments.
If you have an assistantship, you'll fill out a W-4 and have income tax automatically withheld from your paycheck. If you have a fellowship (internal or external), it's most typical for universities to not withhold any income tax (though a few do). In that case, you would need to look into filing quarterly estimated tax - probably not necessary for 2018, but likely required in 2019 and following. 

It really depends on the jurisdiction doing the background check. Usually not too long. For my postdoc, I needed one from the FBI and that took 3 months---usually local or state level checks are much shorter.
But it can also take awhile to get the official letter from the University, so 2 weeks isn't a length of time to be worried.

Sorry if I was unclear: in the role as an advocate for students through the grad student government, it was our mission to help students advocate for their needs. It was not our place to decide whether or not their needs are objectively necessary/founded/etc. To be more clear, in this role, my main advocacy was to talk to students who had an issue in order to learn about their situation and then use our knowledge of the available resources and/or the people we knew in the administration that would be sympathetic to the student's request. Or, in the above case, we might help them look up information to make their case (e.g. searching for policies at similar schools). We would pass on this information or make introductions as necessary, but ultimately the request for a special consideration was the responsibility of the individual student. Sometimes the student comes back to us with updates or shares good/bad news, so I sometimes know what happens, but sometimes not! However, in these cases, we aren't representing all graduate students and we don't directly interact with the Administration as the "Grad Student Government". We simply empower students to be their own advocates.
(Through the grad student government, we do sometimes directly interact with the Administration as the official "Government". These cases are much fewer and when we do so, there is a lot of background work like what you have listed here because now we are indeed representing the entire student body and we need to ensure we are advocating for something that is a overall good for the community and does not cause any undue hardship on any other parts of the community. As you can imagine, this things are much more slow moving and projects like this have timelines of months or even 1+ years. Sometimes they are easy to support [e.g. a campaign to increase everyone's stipends] while others require careful consideration to earn student body approval [e.g. increase health insurance coverage for certain things that greatly reduces financial burden of a few people while increasing the cost of insurance by a few dollars to everyone else]).
Yes, I was referring to Ontario. And yes, you are right that the system does set it up so that people lie. In addition, it also probably sets it up so that landlords can secretly take action against a tenant due to a pet but hide it under some other reasoning. However, I think the fact that a no no-pets-clause exists means people are more open to having pets in their rental units. Maybe my experience was biased, but when we visited many rental places in Ontario, we noticed a lot more places that includes pets compared to California, where the leases all have restrictions for pets and pet sizes. There were even places that charge extra rent for pets.
Another clarification: in my above post, when trying to connect state/provincial laws with University housing, I was thinking of University-owned off-campus lease properties rather than on-campus housing. I don't know how it works everywhere, but I do know that some of the off-campus lease properties from my PhD school had policies that were driven by local/state laws. For example, there was an apartment complex that is meant for (and advertised as) family housing. However, state laws forbids landlords from using family status as a reason to rent to someone. So, there were students without families living there too. State laws did allow for setting a minimum and maximum number of tenants per bedroom (but not on the ages of tenants) so the most they could do is stipulate at least 1 person per bedroom. All of the units were 2 or more bedrooms, so you wouldn't have a single person renting a 2-bedroom there (at half the market rate) so it would mostly be couples/families or people who found roommates to share with.

If the offer letter says the deadline is April 15 then the deadline is still April 15.

You can still be on an internal university fellowship and not have taxes withheld (happens where I go).
This will depend on a number of things: What type of funding (fellowship, RA, TA), what allowances you claim on your W4, and the state taxes in your area (if you keep your residence in a previous state or switch to Tennessee). If you have specific fellowships, taxes won't be withheld for you, but often in those cases you won't have to pay FICA tax, which is close to 8%. Assuming you have no special circumstances, filing single, making less that $38,000 a year, your tax rate will be 12% (more complicated than this: if you go for simple standard deduction, everything after $12,000 is taxed, with the first extra $9,500 taxed at 10%). If you switch your residence to Tennessee, they don't have income taxes, so you wouldn't have to worry about that part.

In my case, doing a PhD with no funding is not an option because I could not afford it. But even if I could, I would never do it: they should pay you for what you do, you are a researcher and thus a resource for them, and doing it without being paid is just wrong. Wrong for you as a person,  and as a valuable professional. But of course this is just my opinion about it...

A couple of things to consider:
1. It sounds like Penn State is not promising you admission to their PhD program (you said "if I'm allowed to proceed..."). Is UW offering you a direct-entry PhD (since it's a 5 year funding offer).
2. Can you stack/combine both the UW offer and your government's funding? $20k in Seattle is not a lot, and when I was applying to PhD programs, UW's offer was the only one I rejected primarily because of their low funding offer (mine was slightly less at $18k/year and no fellowship: TAing the entire degree). I personally would not want to live in Seattle for less than $25k per year. Penn State is in a lower cost of living place, so that offer might go a lot further. (But you should get some number for the PhD funding too).
3. If you end up preferring UW, can you ask to defer the start date by 1 year (especially if this will allow your government funding to supplement your UW funding). This way, you can still take your time.

I finally have a family doctor / GP for the first time in 7 years! Just made my first appointment today.

I don't see any reason to be worried, since you've committed in the portal and secured yourself a spot in the program! 

I think it is a good habit to ensure you respond to emails in a timely manner. To me, this means within a few business days, unless the circumstances of the email require a quicker response. In order to achieve this, I use a system to sort my emails (it's not very elegant....I just use a Gmail label/tag and star it and every morning and after my lunch break, I check my starred emails for things I can respond to). Sometimes, I make a to-do list or set calendar reminders to ensure I get to an important email on time.
Except in rare situations, I would encourage you not to write emails like you said "Thanks, I'll think about it and get back to you.". Most academics have a problem where there are too many emails. I don't like getting emails like this because they say nothing. I don't think it's more professional at all. The exceptions are something that seems urgent (they need a response within 48 hours so you want them to know you are on the case) or when there is something that means you will have a longer than typical response time (i.e. more than 1 week). In these cases, it is helpful to let the other person know you're thinking about it. But don't write something like this if you are going to follow up with the full answer in 3 days or less.
Finally, since grad school, I have been purposely delaying sending some emails. I try to avoid sending emails after 5pm and before 8am as much as possible. But I do enjoy the flexible academic schedule, so sometimes I do work in the evening and take time off during the day for things like less busy grocery stores or doctor appointments. However, I don't want to set the expectation that people can reach me at a moment's notice and get an instant reply from me (and now that I am supervising students, I don't want them to feel like they need to do that either). So, I often write emails in the evening and save as draft. I don't send them until the next morning. I am pretty sure my advisor did this and they set a great example for the group to have a work-life balance, and I am trying to do the same. I think keeping email to work hours only is actually more professional! 
(Of course, exceptions when there is a really important deadline and everyone is working extra hours. But that is the exception, not the norm.)

A couple of things to consider:
1. It sounds like Penn State is not promising you admission to their PhD program (you said "if I'm allowed to proceed..."). Is UW offering you a direct-entry PhD (since it's a 5 year funding offer).
2. Can you stack/combine both the UW offer and your government's funding? $20k in Seattle is not a lot, and when I was applying to PhD programs, UW's offer was the only one I rejected primarily because of their low funding offer (mine was slightly less at $18k/year and no fellowship: TAing the entire degree). I personally would not want to live in Seattle for less than $25k per year. Penn State is in a lower cost of living place, so that offer might go a lot further. (But you should get some number for the PhD funding too).
3. If you end up preferring UW, can you ask to defer the start date by 1 year (especially if this will allow your government funding to supplement your UW funding). This way, you can still take your time.

Once you are sure that you will not attend a program in Fall 2018 and will do the Fulbright ETA, it's also okay to just ask the program you're interested in whether they think you would be more competitive with a Fulbright ETA. Or, another way you can ask is to ask about deferring admissions and ask whether you can be reconsidered for scholarships without applying again (i.e. submit a scholarship-only application).

Do you mean for the mortgage or for the funding from the school? For the mortgage, I am not sure but you would still owe them money etc. There may be insurance or other things you can buy to protect your ability to pay the mortgage but this is outside of my experience.
For the school funding, if you quit your program, then depending on the source of the funds, you may have to repay part of the money awarded to you. I know some people who left their PhD programs in the middle of a term and they had to repay all non-employment sources of income to the school for that term/semester. That is, they did not have to pay back money earned from TA work (and in fact had to stay and finish their TA contract) but the university/department fellowships had to be repaid. For some others, they didn't have to repay the money from the semester but they just immediately stopped getting any further payments. This is why if you plan on quitting, it is important to read the fine print and it is usually much better to quit at the start of a term instead of in the middle of one, if possible.
For finishing later, your offer letter will usually let you know if there is a time limit on your funding. You should talk to the department to find out their funding policies for students who stay beyond their funding offer. Some programs guarantee you funding for as long as it takes, while others only promise funding for X years and then you may still receive funding via TA/RA etc but only if the money is available. I know some PhD students who have to drop to part time and find other work in their last few years in order to earn money (e.g. teaching at nearby schools). 

Yes, tell Carnegie Mellon now that you would like an extension past April 15. See how long they give you! Ask for more time if necessary.
I think it would also be a good idea to reach out to Minnesota after April 15 to check up on your status (so that you know whether there is still a possibility or whether you should take Carnegie Mellon's offer).
And of course, if you have not already done so, you should withdraw your application from Oregon State University now. If Carnegie Mellon is your 2nd choice, then there is no way you will attend OSU so you should withdraw to keep the process moving along. If there was someone who was still on the Minnesota waitlist but was no longer interested, you would hope they would withdraw too, instead of delaying the process, right? 

Hold out as long as you can. So if Carnegie Mellon is offering an extension to April 22, then wait until then. 

Whatever you do, don't treat this person as your enemy! Academia is a small world: your PI may decide to take 2 students after all, you may end up in the same teams for coursework, or you may put off the PI/lab members by being too mean and thus not get accepted. 
First - come up with a solid back-up plan for alternative rotations. It could be that you don't get on as well in this lab as you thought, or the PI's funding falls through and they end up not taking anyone this year. Treat all rotations seriously and be open-minded.
Second - do the best you can in the rotation. It's not just about putting in the most hours or getting the most experiments done. You want to come across as a conscientious (future) labmate who tidies up after themselves, follows the rules, matches the group personality, etc. A lot of the decision-making for selecting new grad students is based upon personality, values and perceived fit, which is hard to change if you don't match up to what the PI is after and doesn't necessarily mean you're a bad scientist if they don't accept you.

Sure! Many Canadian schools do not follow the April 15 resolution (the Council of Graduate Studies, the organization that wrote the resolution is a US organization and only US schools are signatories).
However, some of the large Canadian schools will also set a deadline of April 15 because they know that students also applying to American schools will have April 15 deadlines. The one school in Canada that operates the most like a US school (in my field anyways), including both the April 15 deadline and admitting from undergrad direct to PhD is the University of Toronto. Most other schools do their own thing.
Although I don't know for sure for your fields/programs/schools, most Canadian grad programs operate more like Europe and the UK, where you're admitted directly to work with a POI and it's more like a job offer than the US admission system. For example, for all of my Canadian grad school offers (except Toronto), I was originally given 2-4 weeks to make my decision rather than April 15. And I know that other students hear back later on, in May or June after profs know what kind of funding they will have for next year. 
So, if you are waiting to hear back from a Canadian school (i.e. the top choice waitlisted school you mentioned earlier), I would not assume that you'll hear anything directly after April 15 (although that date may still be significant if others are going to be making decisions on that day). In this case, I would definitely check in with the Canadian school this week to get an update on their timelines. If you are in touch with a professor directly, talk to them too. Like I said above, Canadian admissions do work a bit differently in some cases, where the admissions committee may just approve/deny applicants based on some lower level/generic criteria and then profs "hire"/"pick" candidates from the approved pool (i.e. the final decision is up to the person that's going to be paying you).

If you want the absolute best answer, you should ask the International Office. 
 
However, in general, your I-20 serves as your proof of funding for visa/entrance and status purposes. I also had a copy of my school's offer letter stating the funding amount, just in case, but they did not ask to see it. I do not think you will need the Affidavit of Support from your department directly--the I-20 is a more powerful/authoritative document. I would recommend having copies of any letters of admissions/funding that were already sent to you for your visa interview, just in case, but you don't have to request additional documents.
 
The VO will not ask for more funds than the requirement, unless there is some reason to believe that you will have higher costs (e.g. you are supporting F-2 dependents). However, the VO is expected to go by the cost on your I-20. 
 
You do not need an affidavit of support from your parents because you already have more funding in place than the minimum cost so you meet all F-1 requirements. I think it would be best if you reviewed the F-1 requirements and ensure you provide all documentation that is asked for. It would be best if you did not provide extra unsolicited information!

Co-signing @TakeruK's example above.
Break the "I owe $3,500 in taxes" down into its components to see if each one is reasonable (your Form 1040 separates federal income from self-employment tax into different lines before totaling them). How much is for federal income tax, federal self-employment tax, and state income tax? How does it compare to the calculation above? Was any tax withheld from your stipend income and was that accounted for on the return? You wouldn't have had any tax automatically withheld from your self-employment income, which is why you're facing such a large bill now since you owe both income tax and self-employment tax (15.3%) on that component.
You also have to be very careful not to get caught up in how much extra you owe at tax time/the size of your refund or compare that number to anyone else's (or even yours in the past). It depends both on your total tax liability AND how much was withheld/paid in estimated tax throughout the year. Compare the total tax you owe this year with the total tax you paid last year, and unless something went really awry with one or both returns you should have paid more last year due to your higher overall income and higher self-employment income. Did something change with your stipend - go from assistantship to fellowship funding, for example? If you used to have automatic tax withholding on your stipend and don't any longer, that could help explain why you are supposed to pay more when filing this year's tax return than last year's.
Since it seems like you're long-term self-employed for a big chunk of your income, you should be paying quarterly estimated tax on that part of your income. Part of what you owe this year may be penalties for not doing so, and that wouldn't necessarily have applied for last year if it was your first year in business.
You may find this article (mine) helpful going forward: http://pfforphds.com/how-to-pay-tax-on-your-phd-side-hustle/

Once you are sure that you will not attend a program in Fall 2018 and will do the Fulbright ETA, it's also okay to just ask the program you're interested in whether they think you would be more competitive with a Fulbright ETA. Or, another way you can ask is to ask about deferring admissions and ask whether you can be reconsidered for scholarships without applying again (i.e. submit a scholarship-only application).

As @brainlass said, in the majority of cases, the take-home stipends international graduate students receive in Canada are about the same as the Canadian students. Yes, you will cost the school more money, but typically, most programs address this by reducing the number of international students accepted rather than admitting students with less funding. Or, another way to put it: there is usually enough money for X number of international students, so all of the international student applicants compete for this smaller quota and therefore, you generally need to be a stronger candidate if you want to be admitted as an international student. Note that this general framework is almost the same in every country: non-citizens generally have more limited opportunities.
Whether it's worth your time to apply or not is something that is hard for anyone to consider. A 3.5 GPA is not going to get you automatically rejected from any school. But your application depends on a lot more than just your GPA.
Also, in many fields, Canadians enter a Masters program after their undergrad degree, then follow with a PhD. The Canadian Masters is very different from a US Masters, and you can consider it as the first 2 years of a US PhD program (whereas the Canadian PhD program is more like the final 3 years of a US PhD program). Maybe your field is different though and there is direct-entry from the Bachelor's degree. I only mention this because you should not be deterred if you see that PhD programs require a Canadian Masters, you should then apply for a Masters program there.
Finally, unlike the US, time as a PhD student in Canada will count towards permanent status here! It's not a perfect/ideal system as there are many delays and there are certainly a lot of rules (not 100% familiar with them as I am Canadian so I never had to deal with them) but I know many academics who attend school in Canada and then become permanent residents and/or citizens. So it's definitely possible and unlike the US, your time as a student will count!

Glad to hear that you can find a way to move forward with your project while also ensuring you are doing the right thing!

Hello,
so I have met with my supervisor. It went pretty well. We've decided together that I'd keep the same research project but that I would broaden the population that I wanted to study. So my target population are women in general, instead of women of a marginalized community. And instead of doing multiple interviews, I'm going to conduct two to three focus groups with workers who intervene with survivors of sexual assault. We believe I should be able to finish it all within a year. It sounds like a good plan to me!