Varying Speed of Brushless Motor Within The Same Cycle
Yes it is possible to vary the motors rotational rate during a single cycle, both sensored and sensorless speed controllers keeps track of where the rotor is, and can vary the PWM ratios dozens to hundreds of times per phase, which then alters the effective phase angle your using to turn that rotor, 

Usually this is done to remove the effect of slip angle, but it can also be used to brake the motor if needed, either with an external braking resistor, or using the motor as a brake, which should be kept to a low duty cycle to prevent overheating the motor (all that rotational inertia ends up mostly as heat in the motor)

You will also probably want to check your math on the rate at which you can alter the rotational speed. the motor can speed up or slow down effectively at the same rate (ignoring air drag on the propeller), as its a phase angle of 90 or -90 degrees, 

The actual paper alters the lift of half of the rotor over portions of its rotation, however where you slow the motor will cause a gyroscopic reaction that only applies a force along the shaft of the motor, and not causing a roll or pitch like I suspect your hoping for, 

Technically you can still perform yaw and pitch with 2 rotors, but not roll. and they are a bit muddy as pitch will cause yaw.