Sounds like you've got a good plan going forward, but I'm sorry you're having to live through it
Enmeshed/codependent families are difficult things, add a few narcissists into the mix and it's a big pile of poop. Asserting yourself would definitely cause strive, but doesn't mean it's not worth doing. My ex's family was an issue, I was so glad to get away from it; although they controlled by never planning and then making everyone feel like they said to say "how high" when things like homemade christmas ornaments were demanded from adult children with 24 hours of notice - which somehow meant I had to come up with something while in NYC on business. Your sisters sound like they are easily influenced and in a crappy position too. They want to still have you in their lives, but the family dynamic isn't making that possible. I hope it gets better soon and wish you the best. I hate the holidays, if it was possible to go on vacation then and skip the whole thing, I'd be out of here. My folks, especially my mom, love it, so I'll be with them. Just think, without the family stress, this may be your best holiday yet!