1. I have no idea. I don't use the pockets.

2. The belt holds your race number on instead of pinning it to your clothes. I stick mine in my running shoes and throw it on in T2.

3. I wear a do-rag thingie. I put it on under my bike helmet because I sweat so much. It helps keep the sweat out of my eyes. Then I just keep it on for the run. I look like a dork. I don't care.

4. Unless you're doing an Iron length tri I wouldn't try to change. Think about putting on a T-shirt when you're wet. Ugh. Go for a trisuit or a pair of trishorts and tri top. You just keep the same outfit on the the whole race and you don't have to think about it. Also, there's no place to change in the shorter races.

Just for grins... here's some links to a few race day checklists. I've found it very helpful to have a list that I can look at and check off so that I don't forget anything.
http://beginnertriathlete.com/cms/Ar...eid=108&vote=6
http://triathlon.racechecklist.com/ (This one is VERY extensive.)
http://www.triunify.com/resources/ra...checklist.html