We often do Thanksgiving on X and New Years on Disney (and a few other random holidays here and there). They are some of our favorite cruises. You do end up with more kids on the sailings, but that's usually not a problem. Battery operated lights are not uncommon. Check in the app for all of the festivities. For events like NYE there will often be the "big one" event in a large open area, but much more chill happenings in other places.