Hi DLI! Nice to see you pop in! Hope you, your family and the Corgi kids are all doing well!!!
Lucky you to get a holiday DL trip!!!

I'll be heading to DL in just 2 1/2 weeks and will be missing the holiday fun but and was there last new years for all of it. They'll still have the HM Nightmare before Christmas overlay going and the Christmas It's a Small world overlay while you're there I believe - both two things I consider must do's. They may also still have the Jungle Cruise going as the "Jingle" cruise. Still corny jokes but with a holiday flair.
The nice thing is that DL still has the old FP system so you won't have to try and learn the new one.
World of Color will be a new show for you and you can get FP's for that in the morning that won't tie up other ride FP's for you. And you do want a FP for it. I kind of like Blue FP and getting into the bridge area as the main area is really kind of a crazy mess. Good if you're tall. Not so good if you're short unless you get into one of the few spots that puts you on a rail or in the front. The dining package that Sleepy mentioned is also a good option to get a standing spot in one of the good reserved sections or they have a dessert party option with seats. It's still possible to get a good view without them but you do at least need a FP.
Carsland will be the other new area for you. Radiator Springs is a Test Track type of ride and you'll want to head there at park opening or get a FP right away as those do disappear fast! They have replaced the Aladdin show with a new Frozen one. Haven't seen it yet but I expect it to be good.
If it's been 10 years then you probably rode the new Space Mountain but if not it's a quite different from DL and also a must do. They've also reopened the Castle walk thru since that time I believe. Some very cute dioramas of the Sleeping Beauty tale.