You may also want inspect and clean and inspect the rear caliper and verify guide pins are clean, checking for corrosion or wear of the hardened contact surfaces, relube them with high temp grease. Also before removing the caliper to inspect, use plain water clean the loose road grime first and dry the cleaned unit carefully.
Use a shoe lace dipped in brake fluid to clean the outside of the exposed pistons prior to disassembly, so you do not drive any debris into the bores when spreading the pads/getting them off. The calipers should center directly over the rotor and only a light amount of drag, (swish sound from the pads contacting the rotors) if you are able to elevate bike wheel without interference.
And finally, after any brake work, bleed them in case you got air into the hydralic system. Check before test ride by rolling the bike firmly and make sure braking is crisp, engaging and releasing properly. Don't want to be on the road and not have them stop or lockup.