I don't fully understand your second to last question, Perhaps you are unaware that the centroids of the blade and motor shift off the center of the mast...
Ah OK, my misunderstanding. I thought the discussion was about the reaction of the single blade bending moment.
For one example, think about the number of blades in your single rotor and what effect using 2 blades versis 4 blades will have.
Disk loading is Weight/Area - the bigger the lifting area the better for hover. Blade number N only affects form drag (0.5*Cd*Ro*V^2*S) since blade bending stiffness/strength is not linearly scalable (ie Cd tends to go up with N).
If you are going beyond the disk to talk about the transmission then you had better think about the effect of having a tail rotor, etc. etc, etc........
The best way for any design study is to take proven concepts or models, identify the modification/improvement then work your way through the consequences on each component. It's the only way to accept/reject a new idea before real money is spent.
Mart