We were at Aulani for Thanksgiving this past year. It was a great way to spend the holiday. It was unusually rainy this past year (our local friends, and staff at the hotel all made the same comment) but it did not stop our fun. This was our second visit to Aulani (previous visit was first week of August 2013). We stayed in a 2BR villa - cooked half our dinners in and went out for half.
The last few years there has been a special Thanksgiving buffet dinner held in one of the ballrooms at Aulani. Last year it filled up (two seatings) within a couple of hours. We went on the wait list and were able to get a spot pretty quickly. The dinner was fun and festive with live music and character photo ops. Another option for Thanksgiving dinner would be to get one of the pre-made Thanksgiving dinners from Safeway and then supplement with a couple of home-made sides. I might do that next time.
Let me know if you have any other questions.