Firstly +1 everything that

Firstly +1 everything that Brian Collins said, secondly how far back can you get the camera?
in a room that small a 2 shot will require a wide lens, and how many cameras will you be using, and will the shots me "locked off" or moving? A moving camera is going to take a lot more work to get a reliable greenscreen key.

As a thought do you need a virtual stage?, it means a whole next level of dificulty, could you just make & light a basic set.  I'm not being negitive it's just that to will be almost imposable to get – Wall |> Green cyc |> Hair Light |> Talent |> Camera into that space and get any seperation.

If I was to make a suggestion place the green on the 10ft wall and shoot down the room, at least then you have more distance to work with,

PS it will require a few more lights and A LOT of testing time

Peter