My daughter arrived on Wednesday and has reported very manageable crowds. This AM, she and her sister completed TSMM, RNRC, and TOT in less than an hour without a FP (she is saving her FP+ for later today at MK before the Christmas party.)
She also said that at 1 PM yesterday she was able to change her FP+ reservations from Epcot to MK when she realized she wouldn't be going to Epcot until later. She was able to get Peter Pan, Space, and POC for return times in the next 3 hours. I know, not a peak time, but with the Christmas parade taping going on it wasn't exactly empty either.