The house was great for our stay with a 1.5 year old. Not too many things in their path to keep out of her way. The open floor plan with kitchen/living etc is great, they can play around while you prep food etc. The pool is really nice, though we mostly went to the community one since it had a great kiddy pool. We enjoyed the big assortment of beach/pool toys, as well as the wagon to carry it all. The hosts were very responsive to questions or issues. Our downsides were no baby gates available (even with our own installation) and the really high cleaning fee ($450 for 1 week) when they ask you to do the laundry of towels and garbage already.
We did a toys and car seat/baby gate delivery with babyquip which was fantastic: would recommend them to add what you feel is missing. We even did a better car seat with them, when the rental car one felt unsafe.
For the area:
The beach at Mauna Lani is really nice and small, little to no waves so perfect for little ones to play in the swell. Great (free with the house) shaded parking and good food with the restaurant on site.
The fairmont nearby is worth a visit for dinner at Binchotan.