Well, we've got ourselves sorted, which is a load off of my shoulders and one less thing I have to think about.
We've decided that we're going to have our own Christmas here at home just the three (or four) of us. We have said that we will try to see people when they're in town, but are making no promises, aside from delivery of presents to the in laws and cousins.
I have also put my foot down about visiting us in hospital (we're not actually telling anyone the date if I do schedule a c-section, except my mom, who will be watching BabyDrifter) and expecting us to be anywhere but in our own home if we have a newborn, or to be hosted in any way other than being offered a cold drink and a snack if they come to visit us.
MIL has been sniping at DH that she doesn't understand why Christmas "isn't important to StarDrifter anymore" and he's been basically ignoring that, after telling her that Christmas is important, but right now the baby/birth is more important.
Hopefully she'll get over it. And if she doesn't, well, that's on her.