I also agree about the ADR's but there might be some exceptions. We were in Epcot NYE two years ago. We had no PS (what they were called then) because we were not sure where we would be NYE - my boyfriends father lives in Orlando so we usually just take it as it comes. We got to Epcot around 10:00 am (yes, they were still open - but I think they closed the park later that day). Early afternoon we decided to get something to eat. I must have waited on line at the CS in Mexico for over an hour. Later that night while walking past Rose and Crown my boyfriends just decided to ask them if they could take us. This must have been around 5:00 or 6:00. Well, they gave us a beeper and they were able to sit us outside within an hour. This actually worked out real well because we were able to watch the first show that night of IllumiNations. Of course we stayed for the NYE show also (but not there). We found a place by the lake around 11:00 and waited.
The other thing with the ADR's is because it is NYE you will probably have to leave a deposit. Usually you can get this deposit back if you cancel within 48 hours.
Linda