All of the chassis components and subframes use stretch bolts, apart from the brake caliper carrier bolts.
If the rear tyre wear is even and the car tracks straight, there is no need to touch the rear camber bolts. Save that for when the rear end actually needs a rebush. The bushes back there can appear to look tired on visual inspection, but in many cases they are still fine.
Yep, go with MK2 TT/8P S3/RS3 front top mounts, they're all the same. The bearing is the same as the Golf's/Polo's, but the rubber mounting is a stiffer compound, which you will need with uprated dampers. There is no uprated top mount option for the rear. The rear mounts are more metal than rubber and never wear out.
I strongly recommend the TyrolSport deadset kit to lock the front subframe firmly in place. I would also go with SuperPro ball joints as suggested above to run a bit more negative camber, which these cars respond well to.
Other than that, just check everything over, CV boots mainly as they are fond of splitting, and general wear items. No point lobbing money at stuff that is still sound.