K.S.
the Miami Metro zoo is nice, big area and lots of water spouts so bring their bathing suits and a towel. Take the tram all the way to the back and slowly walk to ward the front. Broward has some nice water parks but i'mnot sure how far south you are staying in Miami. Monkey Jungle is smaller now thanks to the hurricane but they will enjoy feeding the monkeys. If you are going north more and they arent afraid of bugs butterfly world is lovely.