Depends on your spec, but Tesla is rushing for sales for this promo so all custom orders (before a cut off date) will definitely be delivered before the 30th September cut off date.
Yes, while stocks last

For regen breaking - the best advise i can give you is to feather the throttle. The throttle itself is very sensitive, so once you have finally caught the sweet spot for your braking and acceleration, going back to ICE driving style seems like a hassle. Its an extremely fun time for you, take more road trips and familiar yourself.