That’s actually far less than I expected.

Fair point, although NATO without america would essentially be EU and friends. So it makes sense to build up that infrastructure locally.

The idea isn’t really for everyone to give up their militaries, at least in the short to mid term, but to integrate that army with a central command. There are already various integrated divisions and battalions serving with other member’s armies, iirc for example the dutch have attached a pioneer battalion to the german forces that essentially operates as one of theirs, pretty sure the Scandinavian countries have done similar things as well.

I dont know the second thing but even defensively, stealth fighters are much more difficult to accurately aim at with sensors and guidance systems and such, and it also helps a ton if the enemy doesn’t know how many planes you have and where they are from a strategic point of view. Stealth is simply a modern requirement to not be at a severe disadvantage.