1. Should be fine. I think they just want it out of the way enough so that they can work on your chest without having the hair get stuck in your incisions and stuff.
2. You can. That was my biggest fear too, being incapable of doing anything whatsoever. I was on the laptop as soon as I woke up from my nap after the surgery.
3. I stuck with my regular diet throughout. Cereal, meat, pizza, meat, protein shakes, and did I mention meat?

What I would suggest though, is food that is not drippy and messy. Changing your shirt will suck, and if you opt not to wear one, then you get stuck with a sauce-splattered compression vest for the duration that you have to wear it.
4. I was back to drinking as soon as my antibiotics were done (within the week).
5. Whether or not you are good to go depends on your classes and activities. 2 weeks post-op is fine if you have all desk classes and clubs that do not do much in terms of physical exertion, but if you have lab classes or activities where you have to do a lot of decorating or sports, two weeks will not cut it. As for the loft bed, I was back to doing pullups by 6 weeks post-op, so you should be fine to climb into it by 6 weeks. And for book-carrying, the important thing is to keep it rather light, regardless of which you choose to use. From personal experience of hauling a duffle bag to the beach right after surgery, I would go with the messenger bag.
6. I am not sure what is best since everybody's body chemistry is different (and I am only 6 months post-op so my experience is limited), but I have been using mederma for the first 3 months post-op and I think it is working well as far as I can tell. My avi is 5 months post-op if you want a visual of how the cream has been working for me so far.
7. Tip: If you are not naturally a back sleeper, try to train yourself to tolerate sleeping on your back ahead of time and to find out how to make it as comfortable as possible. It is going to be at least 6 weeks of back sleeping post-op. I had a hell of a time going from my bed, to the couch, to a beach lounger, to the floor, and then alternating between the lounger and the couch, until I finally settled for the lounger during the day and the couch at nights.