Both TL and BB have areas for kids who are younger. The lazy rivers are only about 4 feet deep and you can float together. The wave pool at BB is mediocre, only bobbing waves. TL has big waves, but if you are not that far out, you will only get a little wave action. I love TL and I'm not that great a swimmer.
Both places have family slides where the entire family can go down together in a raft.
You can borrow foam jackets for the kids to help keep them afloat.
TL also has the new rollercoaster tube slide where you can go by yourself or with a family member.