My husband and I stayed at Anna and Isabella's apartment along with our 10 month old, and had a delightful time! We most loved the location (away from the crowds but still walkable to anything) and the beautiful gardens surrounding the home.
Regarding the apartment's unique layout - our baby slept in the crib provided by the hosts on the third floor and we slept in the room on the second floor. I was a bit concerned about the lack of bedroom doors to prevent noise keeping her awake, but it was no problem, especially since we were able to use our baby monitor to enjoy glasses of wine at the outside table after she went to sleep.
Anna and Isabella were wonderful hosts! They had the apartment cleaned quickly after the last guests so that we were able to check in early, and also provided us information about train strikes scheduled for our day of departure so that we could confirm our transportation. We would absolutely stay here if we had the opportunity to be in Florence again.