sprocket,
This is only a guess, but the yaw is probably controlled by thrust vectoring of the ducted fans.
It must be more than a gyrocopter because it is intended to travel at 350 knots. It also has to be more than the CarterCopter because of the apparent reverse twist on the blade at 270-degrees azimuth, plus the lack of wings.
Any answers to your questions are only speculation, but here goes.
1/ I don't think that the blades should stall if the 'reverse' angle of attack is not excessive. The airflow will be moving from the thin edge of the blade to the thicker edge and this will increase the drag on the retreating blade, but this drag will assist with rotation.
2/ The large number of blades should offer a number of advantages, such as;
~ a/ Improved lift during hover.
~ b/ Better lift on the retreating side. This is particularly important at mu = 0.5 because the outer half of the blade will have a 'conventional' positive pitch (with positive angle of attack) and the inner half will have a negative pitch (with positive angle of attack), BUT, the middle of the twisted blade will not be providing any lift.
~ c/ Less rotor induced vibration.
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The key to this concept is probably its name [Reverse Velocity Rotorcraft Concept].
For me the concept very interesting, particularly since I started to work and post Internet pages on the same idea, [Negative Pitch], about four months earlier.
I believe that this concept will be more effective if it is applied to an interleaf configuration. If anyone is interested, the reasons can be found at;
Negative Pitch
Dave J.