Remove the caliper pins one at a time, clean off the old gunk and regrease with silglyde. The silicone does not swell the rubber bushing in the lower pin of the caliper. All other lubes/grease I have used have been nasty to the bushing.
Use the new clips if possible. They should match the old ones. Flip them around to see. If they are indeed different just clean the old ones as best you can and grease the channels a little where the pad tabs sit.
Emery cloth grit? Don't know. Just says emery on it. Point is to remove any circular glazing. Did the rotors have a lip on the outer edge?
If you want a detailed explanation of everything Land Rover Brake google "Bodsy's brake bible"