Personal preference (which is what this really comes down to) would be to skip Animal Kingdom. It's my least favorite of the parks, but I have more of a reason too: it's the least decorated for the holidays.
MK, HS, and Epcot will all be pretty well decorated and you won't want to miss that, plus Disney Springs is neat with the Christmas tree trail (if they continue it, which they likely will). With one of your group members never having been to WDW, AK may be missed, but just hit it up on a later trip when you have more time (and maybe skip HS/Epcot that time).
Alternatively, you could also likely skip HS and not miss much. Great Movie Ride will be closed, half of the park is under construction still, and without the Osborne lights it's a close next-to-last for the "most decorated" title. Unless you really like some of the rides/features there.
I definitely would *not* skip MK or Epcot. MK has plenty of decorations and Very Merry if you do the party or not, and Epcot has decorations around the world showcase and the Santas from around the world making appearances that are great to see.
Hope this helps.