This is really not as hard of a job as it looks. Most difficult part is usually getting the piston out.
No need to disconnect the brake line. just pop the piston out with the peddle, then just rebuild, then clean off the brake fluid, mount and bleed.
The rear caliper piston is captured by the housing. It won't shoot out if you're careful.Indeed. I typically just remove the pads, remount the caliper, and stomp the brake pedal tho. Pops the pistons out to the rotor without shooting them across the garage!
True you need something to hold the caliper so it isn't hanging, i have a 6x6x24 inch piece of wood and a drain pan on top of it. I clean the caliper before ripping it open. If your pistons are still good. I keep a spare 1 or 2 new ones just in case i find the old ones pitted or otherwise damaged. I slide the boot over the piston before trying to slide the piston in to the caliper. putting the boot on the caliper first has never worked for me. Having spare parts make the job a lot faster. Once you get the new seal in then slide the boot down low on the piston and then the boot in the groove and slip the piston in. let the bleeder out a little and repeat for the other piston. then clean the brake fluid off the whole thing and remount. put pads in and bleed it out.
This year already I have rebuilt two front sequoia calipers, 2 front calipers to a 79 pickup, 3 rear 80 series calipers and I will tell you, if there is any rust around that seal and inside of the boot, you have to stop the rust or you will be back in again soon. If it has gotten too bad, replace the caliper. You can rebuild on the trail to stop sticking but it won't last so be prepared.