We just got back today from our week at the World and were a bit dissapointed with EMH at Epcot. It was open until 12:00 am but......the only things open are some rides and shows. NOTHING in world showcase is open except rides in Mexico and Norway. They close up the world showcase. So if you are considering going through world showcase, be sure to do it during the day. I believe the rides open were Mexico, Norway, Test Track, Spaceship Earth, Figment, Honey I Shrunk the audience..and I think one more. Crush wasnt open at night.
Hope this helps!