We have eaten Thanksgiving dinner at Crystal Palace twice and will probably eat there again this year. Now, this means you have to join the zoo of people at MK, but my mom likes to do this park this day so we do. It's a sentimental thing for her. We have had a party of 11 and 15. We did have to take either the first or last dinner seating to be guaranteed we are seated together- at tables next to each other. This was not a problem, we ate breakfast in the castle both times and skipped lunch. I had no problem getting a PS, but I did call 90 days out. I would recommend calling 90 days out with a party of 16. The first or last seating for dinner was only for parties of 12 and over I believe, we did not have to do this with a party of 11. They transferred us to group dining.
Another favorite on turkey day is LTT, but I believe this is very difficult to get for that day.
Good luck!