I don’t think frogs needed to have that much mutation. Mainly the mutation gills, aqueous repose, and underwater sleeper.
- Frogs only have gills as a tadpole. They losses it and grow a much more efficient organ called the lungs once they become an adult.
- Frogs are amphibians, they would probably sleep in shallow water while keeping their lungs up.
I think they needed something that makes sleeping while floating comfortable, but not while fully submerged