BabyScientist

Go to one of these people. Even another PI in your department who you feel comfortable with. That is no way for a graduate student to be regarded and consulting people in the program about your problem is the best way to solve it. 

Yes. Sounds like I'm the same kind of PhD program as the poster. 

It doesn't sound to me like he/she is being trained to do research in this complex domain of knowledge. Part of doing a PhD is learning to develop your own ideas, and this advisor doesn't seem to be allowing that to occur. When you communicate this problem to anyone, it shouldn't be posed as "I am a creative person and want to be given room for creativity", it should be posed as "I don't feel that I am being given the proper training/training that will enable me to be an independent researcher in the future."
You do the research that your PI is funding you to do. That's just how it is. But as a PI who took on a PhD student, he has to be giving you the proper training to create a scientist who can do his/her own research in the future, without always having to be directed. 
Discussing this issue with the right people will give you a better idea of whether or not you are getting proper training to eventually become an independent researcher, which ultimately is the purpose of PhD programs in science.

As far as the 3rd recommended goes... If you're asking him in the fall while you're TAing his class, you could bother him about it in person. Give him a deadline that's before the application deadlines.
Otherwise, personally I would advise taking a gap year. I recommend it in general just because I think it gives students an opportunity to mature into people who are ready to be graduate students, and it gives an opportunity to strengthen your application. I'm sure your application is strong now, but it could always be stronger, and a post bacc research experience could give you more LOR options. 

As far as the 3rd recommended goes... If you're asking him in the fall while you're TAing his class, you could bother him about it in person. Give him a deadline that's before the application deadlines.
Otherwise, personally I would advise taking a gap year. I recommend it in general just because I think it gives students an opportunity to mature into people who are ready to be graduate students, and it gives an opportunity to strengthen your application. I'm sure your application is strong now, but it could always be stronger, and a post bacc research experience could give you more LOR options. 

I imagine it depends on the situation. They should understand the social dynamics enough to know not to screw your relationship with your advisor. Theyll likely just give you advice on how to proceed, and only go to your advisor if your directed efforts aren't effective. 

Go to one of these people. Even another PI in your department who you feel comfortable with. That is no way for a graduate student to be regarded and consulting people in the program about your problem is the best way to solve it. 

It will probably help that your masters GPA is better and your research life has been active. The first authorship is good even if it hasn't been published yet - you can still put it on your CV as submitted and maybe ask your PI/mentor to mention it in your LOR.
Im happy to help review your SOP when you're ready. 

Save your money for application fees. It's not a horrible score. Also, as many people have pointed out, most schools are heavily de-emphasizing GRE scores, and some aren't even requiring them anymore. Your CV is strong and your GPA is good. You should be okay. 

Agreed. They don't scrutinize things like that. All 4 of those majors complement one another, so if anything comes the varied courses you took may be seen as a plus. It's a good idea to explain how it came to be in your SOP if the explanation really brings it all together in the context of your career goals. Describe it as applied math/stats in econ/psych and all these fields allowing you to "bring in varied perspectives" to problems you expect to encounter in your chosen career. 

1. Holy crap for an international student a 6 in AW is very impressive! 
2. 161 is NOT low 

Don't take it. Waste of money. Many schools aren't even requiring the normal GRE these days - subject would be excessive. If it was necessary it would be required, and if you can't afford it don't bother. Especially if you have a good GPA in your field, you're already displaying subject competency. 

I think you really have to be aware of budgeting to save during grad school. The worst part is getting paid only once a month and having to factor in how much you'll need before the next month.
As Warelin said, there are too many expenses that are too variable to judge for any individual.
I actually got paid similarly before starting grad school, so I'll give you my experience there. I lived in LA, my rent was $800 a month for a shared room. I'd say I was able to save anywhere from $100-$300 a month, depending on the month. But I could end up pretty broke before my next paycheck, and I got paid every 2 weeks there. 

Well, for graduate schools (at least PhDs), it's actually a statement of purpose. If you convey personality, you're doing it through your writing style or with an anecdote. The SOP is meant to be a statement describing your purpose in applying/going to certain graduate schools. Why do you want to? Why are you qualified? What are your research interests? Why this program? Those are the questions you should be answering.

Why don't you ask your postbacc mentor? I think it would look weird if you didn't. That way they can explain that you have contributed significantly to the project even though there's no publication yet.
Those are solid GRE scores. I wouldn't worry too much about verbal, especially considering that isn't a low score.

I used Kaplan flashcards. Did a first run through where I split the ones I did and didn't already know, removed the ones I knew for sure, and started studying the ones I didn't. I essentially did it alphabetically. I'd pick up a group of like 10 cards, study them until I was pretty confident, did a new group, studied until I was confident, then went back and reviewed the first group to see what I actually still remembered, etc etc over a few days. Worked pretty well. 

Generally they don't request study abroad transcripts, especially if they're already reflected on your undergrad transcripts.
I don't know how being an international student will play in, but I think you should add some mid-tier schools. Rockefeller, NYU, and Cornell are good options, but very highly regarded (though not quite Harvard/UCSF level). Consider BostonU, UWisconsin Madison, MD Anderson, etc. All well regarded schools that are high mid-tier.

Based on how many chemistry classes you've taken? You're definitely over thinking it.

Don't worry about the C+, I had 2 of those in science courses and still got in. Those publications will definitely help, as well as the fact that you had a grant proposal awarded. If the publications haven't been submitted yet, you can still put them on your CV as "manuscript in progress". Pretty solid applicant for most of the schools on your list. Focus on writing a strong SOP that really explains why you want to join these programs, and you may even have a shot at the higher tier schools. 

Based on how many chemistry classes you've taken? You're definitely over thinking it.

They could be on vacation or something. I would send a follow up email. If you committed in their portal, I'm sure you're fine. 

Taking some time to work in your field of interest is ALWAYS a good idea. Programs will be much more impressed with someone who has proven that they know what full time work in a lab for an extended period of time is like. Not too long, of course, but I was a lab tech for a year after graduating before I applied to grad school (meaning it'll have been almost 2 years by the time I'm in grad school), and my most significant scientific experiences have been during that time. Undergrad research experience is experience, of course, but it isn't very representative of full time lab life. My past year and a half or so has been completely different from the part time experience I had in undergrad, and even the full time summer work I did.
I recommend being a lab tech for at least a full year, so you have something to show for it, or maybe considering a post-bacc program, such as the IRTA at the NIH (I don't think one is necessarily much more beneficial than the other). And, wherever you go, emphasize to your PI from the start that you are interested in pursuing a PhD and are serious about completing your own projects, getting on publications, and presenting at conferences. Those are the things that will prove to graduate programs that you're ready to take on 5+ years of research.
Good luck! 

As a Californian, before applying to grad school, I wouldn't have known UNC was even remotely a notable school, but I've always known Brown. 

Haven't even done all my interviews yet and already freaking out about not loving schools I thought I wanted to go to, loving schools I didn't think I wanted to go to, deciding between prestige and comfort, and figuring out how my decision will affect my significant other's career.

Getting into graduate school isn't all about GPA. I'd say that a GPA of 3.5+ would be enough for those schools, but what matters more is research experience, publications, presentations, etc. MIT will offer you great opportunities to research - the lesser known school might too, though (can't say without knowing which one).