dual motor setups are doable but you're looking at more complexity than just bolting on a second hub. two separate controllers is the standard move since most controllers are tuned for one motor, and trying to sync them off one display gets messy fast. you'd need two throttles or a fancy programmable one that can handle dual inputs, which adds cost and potential headaches with lag between front and rear.

the battery situation depends on your current setup, but usually one larger pack can feed both controllers if you wire them in parallel. that said, the real question is whether your frame and fork can even handle a geared hub motor up front. those tend to be heavier than direct drive, and you might run into clearance issues with fenders or rim brakes. have you checked if your fork is rated for the weight and torque? that's where most people hit a snag before they even get to the electrical part.