nobody knows for sure if they will do the dream lights on the castle. And, even if the official word is that the lights are going up this year, that could change on a dime as with so many other things this year.
HOWEVER, I would be surprised if they DON'T do the dream lights this year. Relatively speaking, it's one of the least expensive "big" things they can do to decorate for Christmas. Plus it's one of those things that generates free advertising for the parks and revenue. Between all the people getting the photopass photos of themselves in front of the castle with the lights, or just people taking photos/selfies on their own and posting those all over social media...it's a no brainer.
The cost of putting them up are a small crew for a few nights and a few small cranes that they already own? TBH it's probably net positive revenue for them just on the extra photopass sales alone.
The things I would think that would be scaled back are the smaller areas, especially those that aren't directly tied to revenue. Disney World is normally decorated like EVERYWHERE. Tons of normal sized christmas trees and decorations everywhere. I'm guessing you won't see a lot of the Christmas trees, wreathes, or other decorations in the nooks and crannies of the resorts. They might not do as many of the huge gingerbread houses either.
My guess each resort will get their big tree in the lobby, their "signature decoration" (if any) and some wreaths, lights and such around the main areas, shops, restaurants...and that'll be it.
