Hi magsnden
Awww shucks thanks.
You're daughter and son will have a blast at the Dolphin no question as well as yourselves. Our son was 3 when we first went to the Swan and our daughter was in utero. You couldn't take the smile off his face for a week and a half literally. Every picture we had of him he was grining from ear to ear. The next time he was 5 and she was 1.5. They both absolutely loved it.
They really loved the Grotto pool. It's huge and has a separate kiddie pool for the non swimmers.
I'm not sure how long your trip is but if you go to the Swan/Dolphin restaurants I remember some/all offer a couple hours of free baby sitting while you are dining. We never took it up but it could give you a really nice break.
Make sure you guys walk over to Beaches and Cream in the Beach Club. It's a blast. The burgers and shakes are the best.
We truely love that area. There is so much to just walk around and see with the Boardwalk right there and being in between MGM and Epcot.
Have a great trip!
Andy