I hope I am not too late!
We spent our best holiday ever with our son in Dubai when he was 11 months old. We stayed at Westin hotel and went half board - the restaurant was superb with 5 different food stations. I am Korean and my husband is French, so we do need some diversity for food.
The hotel had a kids' pool and other facilities for kids/babies and baby sitters are ready for you in case you want to enjoy a late dinner.
I don't know much about Atlantis but considering most 5 star hotels in Dubai are quite high standard, it should be ok. Dubai in general is just such a hassle free destination for parents with babies I think.