1) If you have screw caps or a circlips for the top of the stantions to hold in the springs, take these off first as its easier to do when on the bike.
take off front wheel, loosen the pinch bolts and the stantions should just twist down. I would suggest raising the bike further off the ground to prevent them bottoming out on the ground.
2) to take off the stantions from the sliders, there usually is a capscrew socket underneatth. If you don't "snap" it on first attempt, the insides just start turning and you need to make up a lonnnnggg tool out of tubing. I also put the spring back in and with my back to the wall, pushed the spring in via slider, and turned the capscrew off that way.
clean everything out and heat up the old seal and prise out with a tyre lever (taking off clip first). to knock back in, use a plastic water pipe of the right diameter for the seal (ie outer, not soft inner)
3) No idea!!!
Drewpy