At first it was just me and Zatanna, so we picked an apartment with two bedrooms. When Wally showed up, he took the couch. When Artemis showed up, we made room for her too. But five people in a two-bedroom apartment might be much. Especially since we all need places for our stuff.
[Digging around in the kitchen. He grabs a bottle of water and... he assumes she can eat in that form, but he's not sure she'll want to. Still...]