You both should be able to to the lazy river. Some of the tubes have bottoms in them, so you could put your daughter in one of these and either push her around or float on a regular tube and hang onto her tube. The wave pool in TL is better than the wave pool at BB. But I have heard the slides were better at BB than TL (I don't do the slides, so I have no reference). The slides are still pretty good at TL. There is a shark reef at TL where your husband and son can float across the water (it's colder and saltwater) with a face mask and snorkle and see the saltwater fish.
If it's really warm and the parks are crowded, it may be harder to find a shady spot. I know you have to be there when the park opens in the late spring/summer months to get one. I don't think there is much shade at the BB small fry area, but it's been several years since I was there, so I don't really remember. Can't tell you about the TL area.
