I wonder if the "in the parks till 3 am" was during an Eride night? Just regular extended hours would have MK closing at 11 and EPCOT and AK close earlier.
The poster who wrote about staying at MK until 3 AM went on EMH night + MK was open until midnight. Unless they change it, MK is "only" open until 11 PM during the weeks surrounding Easter. Add EMH on Wed. night, and MK should be open until 2 AM for on-site guests.