All of your questions are typical of an owner-in-waiting. But once you have owned the car for a few months you will look back and laugh at yourself for having worried and contemplated frivolties such as seat heaters and noise and heat supression. By all means, heat suppression is worth considering, but these cars are LOUD, HOT and UNRULY no matter what you do and you'll be more preoccupied with keeping you and your occupant alive than worrying about whether or not your arse is toasty. It will be.
Just my .02c.
Jim
P.S. Congrats on the car. Can't beat the ERA/FE combo.
P.S.S. I just crossed the 1200 mile mark today and officially hate the .64 5th gear. I'd really research that if I were doing it again.