Hi Lyle, welcome to planDisney!
You're going to have the best Christmas ever! I personally love the
Holidays at the Disneyland Resort, as you'll get to experience multicultural and diverse music, cuisine, and traditions, and of course the amazing Holiday overlays!
As you are probably well aware,
dining reservations can be booked up to 60 days in advance, so you're well within your booking window. Christmas Day is one of the busiest days of the year, so that, combined with a large party size, is probably what is making it hard to secure dining reservations. But all hope is not lost! Dining reservation availability is constantly changing as Guests do revise and cancel their reservations. So I recommend you continuously check the availability, and also try breaking up your reservations into smaller groups. So instead of trying to secure one reservation for a group of 12, try for two reservations for groups of 6, or 3 reservations for groups of 4. Then when you get to the restaurant, you can ask the Cast Members there if they can seat your group next to each other.
Another great option that I want to mention is the
Quick Service dining option. These do not require reservations, and most also offer
Mobile Ordering through the
Disneyland Mobile app, for a quick, easy, and convenient experience. Keep this as a backup option!
See ya real soon!
Jin