14 mm hex holds the caliper "steady" when it's all installed correctly. Back that out and remove the axle. Remove the caliper from the disc, no need to pull the wheel unless yur doing a tar at the same time.
Pad Hanger Pin is a 5mm hex, holds the pads in place. If it's really stuck, grab the pin between the pads with a good set of vice grips (soak the head end of the pin with PB Blaster first) and wiggle it til the threads break loose. BTDT.
Replace the pad hanger pin with a new one if the above abusive technique is used.