First off I think you have great stats but you come (as I am sure you know) from a pretty populated and extremely competitive applicant pool. Personally I tink your GMAT is excellent, but I am sure being in your applicant pool makes that score just average. So to answer your questions:
1) Maybe. If you feel you can do a lot better than do it. Just make sure you get a higher score.
2) and 3) I only applied to two schools (UCLA and Fuqua) and was dinged by one and waitlisted by the other. My plan for next year was to diversify my risk and apply to multiple schools, I think you should do the same. There are enough good b-schools that you should only apply to schools you like and that you would definately go to if you are accepted.
4) I cannot give you advice on this but I can tell you that I am definately thinking about it for myself next year. My fear is that I might lose my voice, but then again they might just modify your voice and tell the adcom what they want to hear...means to an end
5) I personally think your profile is competitive enough for the schools you applied. Often times I have seen people in your pool of applicants ask the same question and the answer that Scoot, Omari, Linda or Hjort give them is UCLA (Elite) Tepper and UT Texas Austin (both trans-elites)
Again this is my advice as an unsuccessful candidate and is based on what I plan on changing if the Fuqua waitlist does not work out. I just felt it might help you out but then again I am not an expert. GOOD LUCK with MIT
"No! Try not. Do. Or do not. There is no try.