We've done almost everything w/o a height limit. She just hit 33 inches, so we are gonna try the Tommorowland cars soon.
My 15 month old likes (not tolerates, but actually likes):
HS- Frozen sing-a-long, Little Mermaid, Beauty and the Beast show, and that gawd-awful Disney Junior show. She loves all the character meet and greets but for some reason the HS MIcKey is her favorite. She tolerates the Great Movie Ride (dislikes the alien), Toy Story Mania. She got scared during Fantasmic.
AK- The petting zoo was a huge hit. She likes all the Animal exhibits and the dinoland tri ride.The character dance party was also a huge hit. The lines for the characters tend to be shorter in this park and it has the nicest baby center. She's tolerated the safari ride. She didn't like the Lion King, but we saw it at a bad time.
MK- Small World, Haunted Mansion, playground near Splash Mountain, Winnie the Poo, Talking MIckey, Dumbo, Anna and Elsa, Little Mermaid ride(HUGE hit), Belle's Enchanted Tales, merry-go-round, Mickey's Philiarmagic, Monster's Inc Laugh Floor, all the parades, all the characters, loves the pirate show and the dance party. Tolerated Buzz Lightyear, Carousel of Progress. Was not happy about pirates (the dip annoyed her) or Peter Pan (She tried to climb out when she got spooked!) and the Tomorrowland Transit Authority (hates pitch black dark). She despises Wishes.
Epcot- Nemo, Turtle Talk, Mexico ride. There are a lot of characters in this park and the line for Mickey is usually not that bad. Tolerates Figment (dislikes the blowing), sometimes tolerates Spaceship Earth, The Land. She hates Illuminations - she has since she was 3 months old.
If he likes characters, it's worth it to FP the characters. My kid will sit through a show, but I know many toddlers that won't, so that's something to consider. I think all little kids love Small World (colors! music!), but it really doesn't need a fp. He's tall enough for the Goofy coaster - depending on his personality, it might be worth trying. At AK, I'd FP the safari ride.