2 females. Well, normally when gerbils have been kept as a pair for some time, they won't fight.

Temporarily a cage is alright provided there are no sharp corners or loose ends. If your gerbils start to chew on the plastic wheel and house, take them out and place some ceramic or glass cups and bowls for them to play.

Don't worry, they will know what to eat. My gerbils love apples and leafy veges. Already got about 20 over gerbils now