Unfortunately I think Tech's giving you a lot of good advice. With the blower and big cam the Camaro is not intended to be a highway cruiser, so the PowerGlide is really not a bad choice - they were used in a lot of strip cars back in the day, and they're a very strong tranny. If you find you want/need another gear then maybe jump to a built TH350?

Tech's right on for the brake booster, too. A traditional vacuum boost unit is not going to get enough vacuum, especially at idle, and you could very well end up with zero boost when you expect it to be there.

On the surface rust on the brakes, I'd save my money and see how they look after a few stops once you're driving it. It's totally normal for rotors to surface rust during periods of down time, just from humidity, but they clean off the first time you use the brakes.