When we were there in November 4 - 9, 2017, they took down the Halloween decorations on the 6th and started putting up the Christmas decorations. It was probably not complete, but looked pretty festive by the 9th.
We will be there November 2 - 7 this year, so we'll see.
Suess will probably be decorated before USF. Simply because IOA doesn't have HHN. I would assume they would decorate Suess, Hogsmeade and then head over to USF for the rest. Two years ago Suess was decorated about 2 weeks before HHN ended.