I can't speak to the first one. I, too, got suckered into paying sticker.

But...
danidancer wrote:2) I'm starting to freak out about housing. However, I'm still on waiting lists at Columbia, Michigan and Northwestern, so I'm not sure whether it's something I should even worry about yet? If I signed a lease in Ithaca but got in off one of those waitlists, would I just be out my deposit and first month's rent, or would I be liable for the entire term of the lease? I'm hoping to find a place walkable (or I guess bus-able) to the LS in Lower Collegetown or Downtown, but OCHO and Craiglist are looking mighty bleak - am I already hopelessly late in the game? Is it idiotic to wait another month or so to see how these waitlists pan out? I do have a car, so if I need to venture further out and deal with driving/parking everyday, I can. I would inquire about Hughes, but I have a cat.
Once you sign a lease, you're stuck with the terms of that lease. It's a binding contract. Most apartment leases don't have buyout clauses or anything, but if you have a decent landlord, you can usually negotiate something if you do have to back out. It might entail you paying 2-3 months' rent—a reasonable time to find a replacement tenant—but it's better than nothing.
Downtown isn't easily walkable. For walking distance, you're pretty much looking at Collegetown, Lower Collegetown, and maybe West Campus. Try calling Novarr-Mackesey to see if they have any openings (
http://www.ithacastudentapartments.com/) They come highly recommended by a lot of current students. It's about a 20 minute walk uphill, but the bus runs to the bottom of the hill (right to the middle of their various buildings) every 10-15 minutes iirc. So you just catch the bus to class and walk back in the afternoons after shuttle service has ended.
You might also do a forum search, look on the official Cornell 2013 Facebook group as well as our unofficial TLS group for people looking for housing/roommates. A lot have just given into the siren song of Hughes Hall, but there might be some people still holding out for a good roommate.
As for riding waitlists... my gut tells me that no, it's a bad idea. A staggering number of people have been waitlisted as opposed to outright rejected, and precious few people get in off the waitlist at top schools like Columbia because their yield is so high. Most schools' final deposit deadlines have passed, and as we saw with Cornell, a few people
just got in off the waitlist, all on the same day. I would venture so far as saying that those who would have gotten in off a waitlist already have, or haven't.