First of all, have a most wonderful cruise.
As for Epcot, be sure to visit Soarin', Test Track and either the regular (spin) version or lite (no spin) version of Mission Space. Read the signs outside for information and height restrictions, etc.
Kids will also enjoy Turtle Talk at the Living Seas and you folks will enjoy the show, too. If they are into disosaurs be sure to visit the Universe of Energy. In other words, you and they will probably enjoy most everything in Future World.
Don't forget the wonderful Illuminations fireworks at 9:00PM.