If they only want to spend 4-5 hours in the park, I would choose Animal Kingdom over Epcot (I'm the PP at 22:40)
In Epcot, the future world opens at 9 am, but the International Gateway (all the countries) does not open till 11 am. If you are only staying a few hours, and had planned on much of your time exploring the International Gateway, you would only have 2 or 3 hours.
By limiting themselves to morning hours only, they really going to be missing out on some of the best parts of the parks---parades, fireworks, the evening shows, etc.
