Holiday time with family seems like a two-edged sword. Good to reunite with loved ones, spend time together, but also plenty of opportunity for drama.
If you and your daughter get to spend some time alone (go for a drive or something), you can still tell her how you feel, apologize for things, but not actually come out as trans yet. You are just firming up the bond, so that later, at a more appropriate time, you can give her more details, including that you are transgender. For now, I would leave it at you are trying to do better and you are working on some things, but now is not the time to explain. Let her know that she will get the details, but first, you have things that need to be taken care of before that can happen.
I would give a lot of thought to the idea of moving closer to her. If that is something that may happen, is something you want, how does she feel about that? What if you come out as trans to her, and suddenly she is not happy about you being nearby? I certainly hope that is not the case, but you need to consider her wishes too. And her wishes may not be apparent if she is just expressing what your ex is telling her. It is a complex situation, and you are right to give it plenty of thought.
In my opinion, family get-togethers are the prime environment for gossip, so I avoid them, or bite holes in my lip trying to remain silent. Revealing things of this nature is better suited for private one-on-one discussions where there is a better chance for people to absorb the information without a bunch of gossipy input from others. Once they have the information, even if sworn to secrecy, there is a chance that this new information will color their discussions with others. You will know these people better than I, so the route you take would be best for you, rather than what I would suggest.
I know you are in a hurry to get moving again, and that includes coming out to family. Just take a look at the Big Picture to figure out when is the right time is.
Good luck, and try to enjoy the holiday time.
