As someone who is aunt to a 'Toddler tornado' that age, don't forget about Tom Sawyer island. It is one of the few areas of the park the kids can run around and work of some of that titanic energy they have.
Folks have touched on most of the rides so I won't repeat. However, know that certain dark rides might be a bit scary. My niece was a little frightened at first on the Haunted Mansion but got into it pretty fast and wanted to go again later.
Have a great visit! You'll get one privilege I missed...the look on a young child's face in It's a Small World. I have a photo of my older niece's first ride. Priceless!