Resort decorations start coming down overnight from the 1st Jan.
Recently they usually have (at least some of) the MK decorations up until after marathon weekend, which is the first weekend after the 1st January.
Since marathon weekend is a week later this year, I’m not sure they’ll wait that long.
Epcot’s decorations all come down overnight on the 30th December, in time for the New Year stages etc going up. So all their Festive story-telling etc finish on the 30th.