is that busses run for approximately 2 hrs after a park closes so that would be about 10PM in your case. I would think you'd be done ay Chef Mickey's by then. My suggestion would be to walk (its a very short walk) from the Contemporary to the MK bus stop & check. If it looks deserted and I don't think it will, go back to the Contemporary & either take the DTD bus then from DTD the POP bus. Or you could get a cab.
But I think you'll probably be fine. They run busses until the park is emptied out & if the park closes at 8, then Wishes (I assume there's a Wishes performance) will take another 20-25 minutes. THEN they gotta get everybody out.