Eva's apartament is perfect for a bigger group, we visited with our whole family, three couples, one for each three bedrooms, and there's also the sofa cama in the living room that would be a good place for two other people, maybe the more adventurous. The kitchen is fully equiped to make meals, with plates, cutlery, pots, pans and cups. And the view from the terrace is really something!
Note that the Carmel neighborhood is a little far from the city center (about half a hour by metro), but the transport is available by bus or metro, and the wonderful Park Güell is just around the corner.