I have yet to see any parrot continue to squawk when in complete darkness. They have nil for night vision. Shotguns work too. Naturally, it would be predator or prey. Depends on the reptile.
Bearded dragons run and they look funny, but they arent good runners.
Often not at all. There is no stress in being confined. For snakes, there is no stress because snakes live to do 3 things. Eat, Drink, Mate. Outside of that, they sleep and look for a warm place to exist.