EMH means the park will be open 3 hours past closing, which would be 11:30.
Are you asking whether Fantasmic is just for resort guests that night? The short answer is no.
The longer answer: Whether or not there is EMH, Fantasmic is often scheduled at or past closing. Closing doesn't mean everyone has to be out immediately... it basically means the rides shut down and the attractions close. Many shops near the front of the park remain open (this happens at MK too on Main Street) to attract guests as they mosey out.
On an EMH night, it's expected that non resort guests would head out of the park after the show... while resort guests may stay (they wear wristbands as proof so that they may enter attractions).