Eigen

You should always have senior mentors, but I generally encourage my students to choose a junior faculty for a committee chair if they have the option. You can have *bad* mentors that are junior or senior, but when you're picking a committee chair or primary advisor, my experience biases towards the better experience with the junior.
Taking this point by point:
No junior faculty member at an R1 has no experience as a mentor. You don't get to that position if you don't.  Generally, getting tenure at most schools will involve successfully graduating students. For senior faculty, they don't really care if you finish or not- it's incredibly important that you finish successfully for a junior faculty member.  It's unlikely that a junior faculty member is going to move, but my statement qualified "new" assistant professors- the first likely move would be at tenure, by which you'll likely be either graduated or OK to stay on your own at the old institution.  New professors don't necessarily have smaller networks- and they have a lot more sway with the networks they do have, imo. Older faculty can, if they socialize well, keep extensive networks- but they can also fall into the rut of just associating with the same old group while new faculty are aggressively and broadly networking. No faculty member, old or new, is going to have a poor grasp of the broader field.  Similarly, you aren't going to get a faculty position at an R1 without a strong track record for (or potential for) publishing. Newer faculty are much more dependent on getting work out, which is why they're good to work with. Senior faculty can pick and choose what they want to work on, and can afford to take years perfecting a single work- new faculty can't.  Anyway, you seem to have an interesting view that in no way matches my experience with reality- you also seem quite arrogant in your assumptions of junior faculty, most of whom are exceptionally successful in their field or they wouldn't be there. There's a reason many senior faculty say they would not be competitive for the positions they're currently hiring among new faculty.
As said, overall fit with the mentor is the most important property, but taking out obvious red flags (interpersonal issues, major funding problems) and aligning research areas (both are fields you want to work with), I think the better bet is usually going to be the junior faculty member. It might be a bit of a higher risk/reward proposition, but down the road being one of the first graduates of a well-known faculty member will continue to serve you very well as you progress through your career, much more so than being one of many graduates they've had over the years. 
And the negatives of that position balance out by finding experienced senior faculty members to act as mentors- they can provide the insight and experience a young committee chair may lack.
Most of us give advice based on our personal experiences- we don't do multiple PhDs to be able to comment on parallel experiences with different areas. But in the programs I've been in, this has held true- as with the career trajectory of myself and my colleagues, so it's advice I continue to give to my students. 
Regardless, as mentioned, fit is the primary factor- choosing a senior person who's a worse fit for your research interests over a junior person who's a better fit (as is the case in the instances discussed in this thread) just because the person is senior isn't a great idea.

Responding to trolls is pretty much the definition of feeding them. It perpetuates the thread derailing, and makes cleaning up the posts and mess that much harder. 
Report and move on. 

Responding to trolls is pretty much the definition of feeding them. It perpetuates the thread derailing, and makes cleaning up the posts and mess that much harder. 
Report and move on. 

I have a beginning of the semester survey where I ask students to tell me about themselves, and one of the questions I ask is what they'd like me to call them. Sometimes it's a case like this, sometimes it's a "Thomas" who'd much prefer to be called Tom. 
Along with asking preferred pronouns, it's a space for students to tell me what they would prefer, and then I go by that. 

What I've noticed that tends to give a bad impression in past first year students in our program. Some of these, hopefully most of these, should be really obvious. 
 
Don't focus too much on classes, and not enough on everything else. Courses should be a minor part of what defines you as a graduate student/researcher. When your life revolves around courses, and you spend hours not in the lab because you're "studying" for courses we all know don't need that much study time, it makes you seem like you don't really get what grad school is about. 
 
While it's obvious, act like an adult. Be professional in your interactions with people, own mistakes you've made and move on without too many excuses. Don't be the guy that can't get over the fact that he now knows people who are married/have kids/are in their 30s. 
 
That said, treat your work like a job. You're getting paid to take school seriously and do research. If you show up at 10, go to a class, hit the gym for 2 hours and leave at 3, you likely won't make good impressions. That said, you don't need to make school and your work the entirety of your life. 
 
Along with that, lean how to be at least a little bit social. You don't want to be the new department party animal (well, you might, but that's on you), but you also don't want to be that first year who never does anything social with the department, and leaves all the department functions early/doesn't come. 
 
Don't be too cocky. Sure, you'll hear some of the 4/th/5th/6th year students talk critically about a seminar speaker in their area, or a faculty member deconstruct a colleagues research. That doesn't mean you should always do the same. Don't be the first year who talks about how some of the faculty are deadweight/have bad research/aren't as smart as they are. 

Yeah, internal "recruiting" fellowships are used to entice good students. It's a nice perk, but it's not a competitive award that's going to make much difference on a CV.
I would argue there are relatively few school-level fellowships that will make a big difference, but they're still nice to have. 
The fellowships that are really beneficial for CVs are ones you apply to that are nationally competitive.
As you seem to have concluded, I wouldn't weight this heavily in a decision.

@TakeruK has some excellent advice, but I just want to reiterate for lab based people: I always tell my students not to strongly consider a department if there aren't at least 3 people they'd be happy working with. 
Ideally, you get the person you want to work with- but things happen. It might be a tight year, and everyone wants to work with one person and it gets competitive. They might lose a grant, and not be able to afford to take on a new student (or a current student might not graduate, leaving no opening). On the much less predictable and more severe end, they might get in an accident/get sick/die (I've seen all of the above happen to friends). You also might love the research, and find out you can't work with them personally, or have deep personal issues with someone else in the lab and need to switch. 
If you only have one person you want to work with, realize you're taking a heavy risk- if anything doesn't work out with that person, you're out of luck. 

In my opinion, you should not ask for more funding until you are certain you want to go there. At the graduate school level, leveraging funding is not a way to make all the schools increase their offers. Instead, the correct (in my opinion) process is to first pick the school you want to attend (School A). Then, decide how much money you need to attend that school and let the School A know that you really want to attend, however, you don't think you can afford to live on the stipend because of X, Y, Z reasons. If you have a offer from another similar school (similar in both ranking/prestige and cost of living) then you can "leverage" them by saying something like "Well, School B offered $BBB per year, can you match that?". If School A agrees to match it, you should accept School A right away. If they can only go part of the way or cannot match it at all, then you'll have to decide if A with the lower stipend or B with the higher stipend is better for you. But you should not use School A's slightly increased offer to leverage yet another school! 
 
(And depending on field, yes it could matter if the school is upset at you for wasting their time trying to find you funding just for you to use it to leverage a third school. Even if you don't go there--you'll see the same people around over and over again in your academic life).

Dear prospective graduate students, congratulations! Now here's a word of warning as you decide which offer to accept and which to turn down.
Programs may go out of their way in order to make their offers look more competitive than they are. One way they may do this is by describing the highest possible level of funding available and allowing prospective students to interpret this level of funding as "normal".
A real-life example, vaguely described: At one ("top ten") program last year, official financial offers - in which the reality of the funding situation was finally brought to light - were not distributed until well after the deadline of April 15. In this case, some of the prospective students asked for the official offer before committing and were told that there was no need to pursue that formality. The students were told that everything discussed in person and by unofficial email was "binding". When  this cohort finally got its letters they learned they were actually going to make $5k less per year than they had thought, since they hadn't been alert to what was effectively a loophole in what was discussed in person and by email. And since these letters weren't distributed until well into May, it was too late for anyone to change his or her decision.
So in short, get your OFFICIAL financial offers in writing before committing anywhere and then read through them carefully. Programs are competing for the top students, and some are willing to go so far as to mislead prospectives in order to get them to commit.

Personally, I wouldn't advise you to take an offer that's not a great fit to begin with. A PhD is a long process, and especially in the humanities, the school you go to matters quite a bit in future prospects. 
I think if it's such a bad fit that you'd consider MA programs over a funded PhD, you should not accept the PhD offer regardless.

Personally, I wouldn't advise you to take an offer that's not a great fit to begin with. A PhD is a long process, and especially in the humanities, the school you go to matters quite a bit in future prospects. 
I think if it's such a bad fit that you'd consider MA programs over a funded PhD, you should not accept the PhD offer regardless.

Personally, I wouldn't advise you to take an offer that's not a great fit to begin with. A PhD is a long process, and especially in the humanities, the school you go to matters quite a bit in future prospects. 
I think if it's such a bad fit that you'd consider MA programs over a funded PhD, you should not accept the PhD offer regardless.

Personally, I wouldn't advise you to take an offer that's not a great fit to begin with. A PhD is a long process, and especially in the humanities, the school you go to matters quite a bit in future prospects. 
I think if it's such a bad fit that you'd consider MA programs over a funded PhD, you should not accept the PhD offer regardless.

Personally, I wouldn't advise you to take an offer that's not a great fit to begin with. A PhD is a long process, and especially in the humanities, the school you go to matters quite a bit in future prospects. 
I think if it's such a bad fit that you'd consider MA programs over a funded PhD, you should not accept the PhD offer regardless.

I just differentiate it because I have peers in other programs that meet with their committee regularly as a group, which makes it a lot more important to choose mentors. 
Personally, I chose people for my committee who I felt opened doors of some sort- instruments I wanted to use, connections to a different program/program type. Some of these were going to be mentoring relationships, others were just someone well placed who could speak to my abilities as a scientist. IMO, having people on your committee that get along with your advisor is the most important- and sometimes it's good to have mentors that don't. 

Just remember that you should not put "candidate" until you actually are one.

Your committee usually raises you to candidacy following approval of the prospectus for your Thesis/Diasertation. Before that, you're a PhD Student, not a PhD Candidate.

You're asking questions that essentially come down to comparative personalities, for which you'll get every possible answer. 
Some PIs will take the initiative, some will disappear and you won't see them at all. 
Personally, when I take my students to conferences I want them to do a mix of exploring and networking on their own, and introducing them to people I know. I usually only introduce them to people that are close colleagues, not the people I'm striking up new relationships with. 

My wife and I had been married a couple of years when we started grad school. We were definitely the minority, and there were some weird reactions at first, but people got over it pretty quickly. 
There are definitely stresses to grad school, but I'm not sure they're so much more intense than some high-stress jobs. 
Personally, I found having someone that I knew I could count on to be a support was immensely helpful, and it also reminded me that there were things outside of school that were important, and helped me ensure I took time to keep my life balanced as much as possible. 

I wouldn't worry much about the committee, but I'd definitely suggest picking up a senior faculty mentor or three. I did my PhD with a fresh prof, and it was really helpful for gaining independence and learning how to set up a lab and collaborations and that has been great for my career. 
But he wasn't much on mentoring, and I was completely on my own for the job market- he wrote what I hear are great letters, but that was it. 
I had senior mentors in my department, as well as people I met through conferences that were a lot more helpful in those areas, but who's lab I wouldn't have wanted to work in. 
As an aside, committees are pretty unimportant in a lot of the bench sciences. I met mine three times- once to ask, once for my prospectus, and once for my defense. None of them had any role other than evaluating my work. I know committees in other fields can be more involved. 

My wife and I had been married a couple of years when we started grad school. We were definitely the minority, and there were some weird reactions at first, but people got over it pretty quickly. 
There are definitely stresses to grad school, but I'm not sure they're so much more intense than some high-stress jobs. 
Personally, I found having someone that I knew I could count on to be a support was immensely helpful, and it also reminded me that there were things outside of school that were important, and helped me ensure I took time to keep my life balanced as much as possible. 

My experience has been that the overall culture and atmosphere at larger universities is relatively unimportant. You will encounter it a lot less than you will the culture of your research group. There's also going to be enough chemistry grad students that you'll likely be able to find a group you get along with. 
Ideally, you shouldn't go anywhere (imo) that you don't have at least 3 faculty members that you feel are good potential mentors. You can't get a perfect feel for someone until you're in their group, but through talking to them and their students/post-docs during a visit, you can get a pretty good idea of what they're like. Having 3 people & groups that seem reasonable after meeting with them means that 2 of those groups can not work out and you'll still be OK. 
Also, the question's you're asking here are things you should be asking the graduate students on your visits. You get a lot more (and better) information talking to people face to face than you do online, and it's a lot easier to pick up on subtle cues that way. 
Back when I was applying to grad school, it was pretty clear after visits where I felt like I'd fit best, and where I felt like it would be a stretch. That's the whole point of visits. 
Take notes while you're there, and then at the end sit back and visualize where you felt most at home, and where you felt most excited about working with a group of people. Hopefully those are the same place.

If it's a job, yes.
RA usually denotes a research assistantship, which while that's your nametag may or not be your actual job description, as it usually refers to someone who's doing it concurrently with a degree. 
You're more likely to be able to negotiate a raise, especially in light of another job offer- and especially if you're truly willing to leave for that other job. Different grant budgets are different- some require pay at particular levels set during the budgeting, some allow more flexibility on the part of the grants PI. Some institutions are also better than others (ie, public vs private) in flexibility of pay. 
My advice for negotiations is to know what you want, and ask for something fair and honest. You can easily present your case as not wanting to leave, but needing to make ends meet especially in light of this other offer. 
You can also "soft" negotiate, where you inquire as to the potential for a raise without directly asking for one- the response there tells you how likely you are to be able to negotiate. 
For most RAships, it's not typical to receive even COL raises, but sometimes they are built in. When they are, it's usually small and not something negotiated, but something built into the payscale. 
I would also suspect that if you want broader advice on job negotiations you ask in the Job forum- that's the only one that really has much discussion of people not currently in/applying to grad school, and you'll probably get more replies there from people who've been in/are in similar places. 

I'll make this my last post here as well:

The alternative is that they (a) didn't know that the GPA would be a make or break factor (it might not have been in the past, dean's change) and (b ) they may have known it was a fight they would spend several weeks on, and still not win- making it not worth it for either the applicant or the department to drag out the whole process. They might have fought it out and still had to rescind the offer, but closer to a month after they made it than two weeks.

How is it not a helpful or fair comparison? A PhD offer is quite close to a job offer- you are being compensated for services provided, either research or teaching.

And how common offers being rescinded are is debatable. There are a nice selection of cases where offers have been rescinded on this very board.

I feel for the OP, and I think it's quite sad it happened, but I would not consider this unprofessional, nor do I think it is likely the fault of the department.

I sent thank-yous everywhere I visited, both to the faculty, admin's and grad students I met.

More of a "Thanks for taking the time to meet with me, I really enjoyed talking to you about your research, I found XXX part particularly interesting", etc. More of a way to thank/start a dialogue with them at the same time.

Thanks to the grad students for time with you (if they spent it) and the admins for setting things up are also nice.