lemma

Come on, an Ivy institution doesn't particularly have a fierce competition for grades. They're not that different from other well-regarded public and private universities, and in fact, it's pretty well known that they're pretty darn generous with GPAs, especially Harvard. I think you maybe Cornell, with 4.3 GPA system, has a fierce competition, but this doesn't extend to every single Ivy institution. But I frankly don't think adcoms will see your degree at an Ivy institution as an excuse for having a low GPA. I mean, it's harder to get a good GPA U Chicago and UCB than most Ivys, and students at top USNWR 30 universities all know this. And of course, adcoms are going to know about it too. Ivy students overrate themselves and they really gotta stop doing that... Ivy is just the name of a sports league, not schools that are hard to get a good GPA.

Good luck! If you were in touch with anyone at the program, you could use this opportunity to write them to say you've submitted your application and ask if they know what the expected timeline for decisions will be. This may or may not get you a satisfying answer, but is worth a try.
While you wait, the best thing to do, if you can help it, is find ways to occupy yourself. Work, read, exercise, travel, do your coursework/research, etc. Do NOT check your email or the Results board obsessively -- that is a good way to drive yourself crazy but not to actually speed up any answers. I often find that the best way to wait for something important is to literally forget about it until a set reminder pings to tell me to check if anything has changed (I routinely wait for multiple important things these days years, so continually checking wikis or the rumor mill would have driven me insane by now. I had to learn to stop doing that!). I just do my best to keep my daily routine, and I'm busy enough that it's not hard to put it out of my mind (until someone remind me!). It's a learned skill, though. The first few times I waited for something important (like grad school apps) I did sort of drive myself crazy refreshing my inbox. I think I can reliably say that it in fact did not make admissions decisions arrive any earlier... 
As for the notice issue, work out when is the latest point at which you can give notice and start the program on time. I think it's fair to write the coordinator a couple of weeks ahead of that date and say something like "I'm writing to express my continued interest in your program and to ask if there is any update as to when I might expect a decision on my application. The reason I ask is that I would have to give notice at my job by Date to be able to start the program at Later Date. Your program is my top choice and I'd be very excited to attend. Please let me know if there is any information I can provide to assist the admissions committee in making its decision" (or similar). What is sometimes annoying is what people bug profs for no reason other than they're anxious, especially if they do it too often, but if they have a good reason,  they will understand.

I just wanted to add that although this definitely sounds unprofessional, you never know what is going on behind the scenes. My cousin (40s) has brought her husband along to events before which were not designed for him to attend because he was suicidal and couldn't be left alone. This obviously wasn't something she was willing to discuss with people outside her inner circle. 
Maybe he was traveling through the city and didn't have anywhere else to go for that period of time, maybe she or him were having a hard time for whatever reason, maybe was just unprofessional. You don't know. Whatever the case, I would always favor dialogue over accusations as a first step.  

The general gist of the above is spot on but investment banking is literally elementary school math. The GPAs you need to end up at a top three firm are higher than to get into a top five PhD in most fields, but that type of brainpower doesn't come into any of the work. 
Hard work is more what makes you successful, and attention to detail. It's not intellectual work. Try picking typos at 2am when you've only gotten four hours sleep the night before, and you'll appreciate that it's a different flavor of difficult.

Definitely don't do it. US schools are terrified of having students who could be suicide risks on campus from a legal perspective. 

I'm taking the GRE soon and I've only taken three practice tests (most of my studying was vocab or questions which weren't in the test format). Before I did practice tests under test conditions, I thought I'd score < 165 on the verbal because of pretests, but that wasn't always the case on the practice tests. My scores were 170Q/166V, 169Q/169V and 169Q/163V in that order. I'm a little worried that my verbal dropped in the third case - are such drops unusual? 

I'm taking the GRE soon and I've only taken three practice tests (most of my studying was vocab or questions which weren't in the test format). Before I did practice tests under test conditions, I thought I'd score < 165 on the verbal because of pretests, but that wasn't always the case on the practice tests. My scores were 170Q/166V, 169Q/169V and 169Q/163V in that order. I'm a little worried that my verbal dropped in the third case - are such drops unusual?