Here is what I could find (looks like the Epcot monorail will run for 90 minutes after the EMH closing of MK):
There are three options for the monorail system. The resort monorail, which stops at the Polynesian/ Grand Floridian/Magic Kingdom/Contemporary and Ticket Transportation Center, usually begins running at 7am and runs until 2 hours after the latest park closing between Magic Kingdom or Epcot.
The express monorail, which runs from the Ticket Transportation Center (walking distance from Polynesian), to the Magic kingdom starts around 30 minutes before the opening of Magic Kingdom and runs until Magic Kingdom is cleared for the night.
The Epcot monorail, again originating from the Ticket Transportation Center begins its day right around 8am and will run until approximately 90 minutes after the closing of Epcot or Magic Kingdom (which ever closes latest that day)