Yes, the pump power will come from a 4 pin molex from your psu, and then connect the pwm plug to a aquaero 6 pro pwm port.

The aquaero 6 controls fans digitally, so you probably will not NEED a heat sink for it, but it is not expensive if you want to install one. They look cool.

I am not familiar with the GMR FlowMeter product, but if you are buying an Aquaero 6 Pro, you may want to get a Flow Sensor that takes advantage of the aquabus interface of the Aquaero 6 Pro. Just determine which of the 3 sensors best match the flow volume you anticipate having in your loop. Additionally the MPS flow sensors are not mechanical, so they should effect flow rate less.

I have one of the MPS flow sensors for the new radiator system I am building, but it has not been used in anger yet.

I have been advised by AquaComputer to not place an angle fitting at or near the inlet, as that introduces turbulence that effect the sensors. And that makes sense, as turbulence, by definition, has varying velocities in the stream which will then confuse the device.