Success! Had a grand time. Everyone was welcoming and interest(ing/ed), met 5 of the 6 medievalists and several grad students who all seemed cool, and am looking forward to inserting myself into the beating heart of the city come fall. Was excited before, am way excited now. The housing I'm not so much looking forward to but it will work out.
Shortstack, were you at the afternoon/pre-dinner reception? I possibly overheard someone mention your name, but I was too busy talking with folks to find out!
From what I gathered, cohorts are generally 8-ish, sometimes up to 11. The campus is nice and the department (and other departments--history, philosophy, and theology were represented at the receptions as well) overall seemed cool. I don't know the size of the incoming cohort, and didn't hear about the wait list, sorry. If it's getting down to crunch time I'm sure the DGS would be fine with giving you information (I emailed the DGSs of both places I was waitlisted at, one of which turned into an offer).
If you have any questions that I may have the answer to from my short time there, I'd be glad to respond!