I've stayed at both the Park Hyatt and the St Regis. Most resorts will do a beach dive on the house reef for your acclimation dive before taking anyone out on a boat.
The St Regis was absolutely stunning, but as far as a dive op goes I wouldn't recommend it. When we were there (July 2019), the dive shop had its own schedule. MWF 2-tank boat dives, T TH 1 tank boat dives. You pay a boat fee each time, and they weren't too keen on setting up another dive of the house reef. Depending on your stay, this may limit the amount of diving you get in. For example, we were there Sunday through Friday, so really only got 2 days of diving in when I would have preferred more. Of course, you could choose to do a one tank boat dive, but I decided against it. We were able to do a night dive and came across a cuttlefish, which was fun to see.
The Park Hyatt is a bit opposite. They were happy to accommodate 2 tank dives, plus night dives. I felt like the house reef was healthier at the Park Hyatt, and much preferred the diving from their location. However, there isn't a kids club, and many guests gave a bit of a side eye to the people who showed up to the pool with 3 kids who were splashing around. It definitely isn't as kid friendly of an environment.
I had to cancel it, but I'd also look at the Westin. It is located in Baa atoll and isn't too far away from Hanifaru Bay for Manta Rays. There's also a kids club as well on site, so it might be a good blend of both worlds.
