I'm sure all the kids would love Toy Story Midway Mania.
Allot a couple hours and a change of clothes (down to underwear and socks and shoes! and bring a couple towels) for bug's land. Let them play in the water play areas if they are on. Be the bad influence on other peoples' kids, LOL. Relish the "but that kid is getting wet" comments you'll hear.
OK, I'll stop. But seriously, some of DS's most fun days were the days he got to get drenched in the bug's land waterplay areas!
And the rest of bug's land is awesome as well.

I actually think people should bring their little ones there BEFORE going to Fantasyland. All the rides are out in the open, no dark scary lines or buildings at all. Unlike Peter Pan, Alice, Mr Toad, Pinocchio, or Snow White.
They have a noisy play area near the Farmer's Market...get your earplugs, snag some lunch or a snack, and let 'em bang away! Superloud, superfun for kids.
Monsters inc ride is so awesome!
We love DCA.