I hadn't considered the idea of magnetoresistance, considering how they're much more complex than just a copper PCB, as they typically require ferrite alloys. But this seems to be what they are, and ALPS ALPINE seems to have an unsearchable amount of patents (when I glanced on Google patents, the nu...

I don't have one of the few models of controllers that have 3pin sticks, but in theory a 3pin pot should be compatible with with a 4pin board and vice versa. The issue is how do you connect them. You might get away with bending pins 90° and putting some electrical tape on the pads, and using jumpers...