i went in may. we didnt stay the night, we just drove. so i dont know about hotels.
i believe the party started about 10pm and went to 4am. they had special "dance" spots some including raves and the soap sud dances. there were special fireworks that played modern, chart topping music. not disney music. uhm, they had special merchandise and you could meet mickey all dressed up in a cap and gown. they also have live stage perfomances. we had a couple groups i dont remember but the fray was there.
honestly, i went hoping to have a blast and was sourly dissapointed. a whole bunch of highschool kids left to run around in disney was stupid. they were rude and abusive to all of the rides and cast members. ive never seen so much security before, and ive never seen cms have to hide in the ride sets in order to yell at people to sit down. they only have the quickservice food stops open, so nothing fancy.
but if you get to go, i hope you enjoy it. :3