My 4 yo daughters picks:
MK: Peter Pan, 7dwarves, enchanted takes with belle(hardest ones to get). Tomorroland speedway, buzz, jungle cruise, pirates (as 4th/5th FPs)
The princess meet and greet
FP go early, so those should also be a priority if meeting princesses is important to you.
She also loved pooh, teacups, small world, under the sea, dumbo, barnstormer and Aladdin, all of which are fairly easy to do without FP Early in the am
Ak: safari, navi river,
Lion king show
Epcot: Frozen, spaceship earth, nemo
HS: toy story, beauty and beast