Is there anything inside the feet that would break being cut off?

Not sure exactly what you mean by feet, but if you are referring to the pieces circled in red in the picture below my answer would be yes you can likely cut them off. I would recommend completely disassembling the controllers and using a very fine toothed hacksaw, bandsaw, or coping saw to cut that piece off. Be careful not to cut into where the buckle lock button is near the rail (Right controller, Step 4, Picture 2, circled in light-blue). You would also not want to disturb any part of the plastics that the rail sits in otherwise you risk it not making good interface with the switch.