You inspection has revealed the reason why your disc is showing excessive wear on the outer section of the rotor - your guide pins are bent. Or more likely the mounting bolts holding the slide pins down are bent. If you can get it apart you might be able to rescue the caliper assembly depending on how messed up the slide pins are. The 'pivot' pin (the upper slide) is a bolt with either a 10 or 12mm head. You have to get the caliper off to undo it. But seeming the disc rotor is fubar you might as well go looking for a complete replacement assembly from a JY.