1. It will be busy, but more than likely not Christmas Saturday busy. Don't expect it to be to far off, but the rides will help absorb some of those crowds and make it a bit easier to see the shows.
2. I think this may be the first time they've done later hours at a time other than Christmas and Moonlight Madness, so it's hard to say. More than likely you're right, but until they release show schedules for that day, we don't know.
3. They'll release all the food extras right after Festival of Wonder is done, but more than likely it'll be several BBQ booths in Red Gold or something like that, and maybe a BBQ nachos/ fries at one of the food locations and not much more different food wise.