I can't answer all of these but I'll take a crack at a few.
1. It will be empty, you probably won't have to wait in line for anything. Some of the merchandise may be sold out, though.
2. I've only ever taken the bus, so I can't help with this one.
3. It depends on which corral you're in and how much you care about being towards the front of it. Corral A closes 20 min before race start (so 4:40am), corral B closes 10 min prior to race start. If you show up after your corral is closes youd just fall back and join a later corral. If it's important for you to be at the front of your corral I'd be there by 3:30 at the latest. Others who have more race experience than my measly two races should weigh in with better opinions, though.
![smile :) :)](http://www.wdwinfo.com/images/smilies/smile.gif)
4. There will be instructions on the back of your bib for linking to your photos. I don't think you need a magic band, it's all done by your bib number (but I haven't managed to stop for a character yet, so someone please correct me if I'm wrong!)