Driving the rotor
This idea of driving the rotor with the inner region doesn't work in my mind, here is the logic.
The central hub area is completely stalled and the blade area some distance out from the hub is likely at a very high angle of attack close to stall as well. So it would be unlikely that the inner region could extract any energy from the airflow and then transfer that energy to drive the outer rotor. It just does'nt work that way, the outer rotor would need vastly more power because it goes twice as fast and therefor has the majority of the drag.
So how could the inner rotor drive the faster tip area?