Typically no...everyone moves in on the same day.
No they don't do survey matches or anything like that either. Until this last set when they switch ed to more of an online checkin system...basically it was the people next to you in line were your new roommates. So if you knew no one, the person in front of or behind you most likely was going to be your new roommate. That's why kids had to line up TOGETHER if the wanted to room together.

And when DD was in the program if you could provide evidence someone else in the unit was eating your food that was grounds for termination. That, along with under age drinking, is a BIG NO NO to Disney. I "believe" they treat/consider that the same as theft.
And I wasn't saying don't attempt to set ground rules the problem is in the larger units, kids can come and go from the program....wait until your kid comes home from a late night work shift and somebody either left the unit or got termed and their key no longer opens the door. Whenever someone leaves the unit, the lock has to be changed and everyone has to go get new keys. It can be a royal pain. It's necessary and done for everyone's safety but what an inconvenience. And when new kids join the unit the may not agree to what the others originally agreed to. The College Program can be fun but I think housing is probably the biggest challenge of any....at least IMO.