The key to good green screen lighting is separation.
With out separation of the subject from the green screen you're kinda lost.
To achieve this you not only need to light the subject and the green screen you need to put a kicker (back light) on the shoulders and head of the subject to give them some dimension.
With out this back light on the subject you will have a hard time making your animations look realistic and not flat.
The evenness with witch you light the green screen are key as well. I would suggest borrowing some
cyc units or maybe some fresnels.
JH