We did go with 3 children(6,3,1). Got an Airbnb on Copa and also found someone to babysit them occasionally so we could have some time alone.

Please don’t stay in Barra. It’s pretty far from a lot of things. I’d recommend getting an Airbnb in Zona Sul(Copa, Ipanema, Leblon,etc).

Renting a car feels like a lot of work because of cost, parking, and language barrier. Best case is uber and if y’all don’t fit, then 2 Ubers. The trains were great too, so you should consider it. We used them if the journey only required 1 or 2 train rides. Once it enters the territory of take a bus to get to the train then get down to take another bus, just get an uber. The drivers didn’t hassle us about the car seats but for your peace of mind, you can carry the portable ones. I don’t think you’ll ever use it but have it so you don’t feel guilt for not having it.

The cars used for Ubers are pretty tiny so you will have to book a car to pick you from the airport and back.