Well sir, I am not sure if they donate or not. We usually do troops just because we are asked to. We generally do not ask for donation's for any event. We do however encourage it. That is stated
on the form that has to be filled out for an appearance request. Most of us were happy to sign up for this one just to be able to troop the kingdom.
The answer to the question " are those 501st troopers " is yes accept the ones in the front. They are Disney cast members. If you look close enough you can see the difference in the armor.
Vader is also theirs. Even at Star Wars weekends they use their own Vader, Fett, Zam, etc.