I hope someone gets back to you soon, as I'm curious about this as well. I was trying to think of places in the Lansing area (E. Lansing, Okemos, etc.) and I'm sure there are some open for Thanksgiving, but the places I just checked were not going to be open. Does your hotel have a restaurant that might do a buffet?
Some other places I thought MIGHT be open are Coral Gables, Beggars Banquet, or Stillwater Grill.