When we stayed at the Rosewood we ate at the Thai restaurant at Banyan Tree (very good) and also toured a villa there—the Rosewood IMHO is much nicer and more upscale. Better maintained and judging by the reviews, better service. The Rosewood butler system actually works well which is not the case at most places we’ve been.. There is a new adult only beachfront pool and lounge section at Rosewood that looks nice that one of you can use when the baby is napping.
For room types at Rosewood, the ocean view pool suite worked really well with our 2 year old because it had sliding doors between the living room and entrance area, and between the entrance and bedroom (the floor plans are all online). We put the hotel provided crib in the living room, closed the sliding doors that separated it from the entrance door such that we could get room service at night without disturbing her. Very helpful because the hotel babysitter could come at night after she was asleep and closed off in living room. Really good setup. There is a nice rooftop plunge pool (large) with great water view. With a small baby and likely a 3 nap a day schedule I’d recommend you get a room on the beach side as opposed to lagoon side so you can take turns going to beach etc. quickly while baby is napping. That suite or the beachside lagoon view suite would be my category recommendation.