I have a tip. Whenever you make that first invitation and she turns it down, do not try to get her to accept another invitation. It is fine to ask her to join that first time, but don't just keep pushing and don't throw in a different invitation.

FWIW, she probably would feel uncomfortable around your family the first time.

I think she gave a clear signal she didn't want to be with you Thanksgiving if she is choosing to go to the movies with the kids (this far in advance). So, pull back some.

It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!