If you hope to put them outdoors then they definitely need to be in a cage. They can and do climb or jump off trees to get away. That's not to say you can't put a cage around a tree! =) I have cages around a jasmine plant and a schefflera tree outside for my little buddies.
Ficus is a good indoor choice, and there are lots of cool ficus trees to choose from. But like JJ said, they still need the UVB and the correct temps in doors.