Hi we went there last year. Very nice.
Much better than any of the water parks at Disney. Yes they have a very large area for children. It is not just for little ones though, any age can go in. They do have staff walking around with measuring sticks measuring children to see what colour life jacket they need to have on. You will need to stay with your little one though, there is so many nooks & crannys there for them to get behind....

psst: the dolphin plunge isn't that great though. You go so fast in it, you can't see anything through the tunnel anyways.