1. I recommend you get an oil cooler. If you're worried about tracking your DD, you can purchase track-day/HPDE insurance from Lockton.
2. No, but you do want to change more often than factory intervals, as you ARE driving your car harder, and subjecting it to more heat, wear, and friction.
3. That increased travel is degraded brake fluid. Lack of response in the brake pads relative to pressure, is brake pad fade. You want to upgrade both your pads and fluid, for track duty. You can swap in stock pads between track days, but most weekend warriors eventually opt to leave in their race pads permanently. Once properly bedded, noise isn't an issue, and the only real consequence is increased brake dust.
4. It depends on the organization; ask them if it is a "self-tech", "at the event", or if it needs to be done professionally, and act accordingly. Some best practices are to always check your oil level, tire pressures, and lug-nut torque.
5. Check out this thread.
http://www.ft86club.com/forums/showthread.php?t=25485
Great questions, and you're asking in the right place. We're here to help.