Last time we went with our just turned three year old and his two year old sister. As you mentioned, they loved the fantasy land rides...especially Pooh, Peter Pan and the teacups. My son (the older) loved the tomorrowland speedway (he rode with Dad). Small World was under refurbishing at the time. My son also loved the barnstormer. They both liked Aladdin's Magic Carpets, too.
As for MGM, they liked the great movie ride, Muppet Vision 3-D, the Beauty and the Beast show, and the Playhouse Disney show. The Little Mermaid show was fine for them once and the next time they freaked out about the time that Ursula makes her appearance. She was scary to them.
At AK, all we did was the Lion King show. The park was really crowded that day with field trippers, so we didn't even do anything else. Sorry, I'm not too much help there!
At Epcot, they did make masks. I thought they might be too little, but they really did like it. They also loved the toy shop in England (with the Thomas Train). They enjoyed the river boat ride in Mexico and the Norway Maelstrom. Caution: there are some kind of "scary" looking trolls in there, so just a heads-up on that.
The thing my little ones most enjoyed on that trip were the characters. They loved to see them, seek them out, and then talk to them. It is a magical age, because everything was "real" to them.
Enjoy!