As best I recall, the College Program participants were supposedly being housed in the Fairway Villas, not the Treehouses. I'm fairly certain the Treehouses are indeed empty, and currently reside on protected land. However, when I asked some random CP cast members about the Fairway Villas last year, they had never heard of anyone being housed there. So who knows - maybe this was a temporary thing, or maybe just a handful of "overflow" rooms are being utilized there.
I hadn't heard about Disney possibly removing the Treehouses' protected status, something I'd really hate to see occur. Anyone know what type(s) of development Disney might have in mind here? The combined Vacation, Club Lake, and Treehouse Villa areas is quite a chunk of land for just one resort (making me wonder if some rumors are possibly getting mixed here). The Treehouse villas are unique accomodations, and certainly interest in them remains. Indeed, this has come up before in at least one Rumors board thread. Operated as part of an adjacent resort (OKW, Saratoga Springs, or even French Quarter), Disney could still fill those rooms.
I could swear the Fairway Villas did survive, until recently if not still around, but then I wasn't exactly looking for them last time either. I'm thinking a little exploration may be in order come the end of June .......maybe a round of golf or a boat rental.