1. a. Yes, if you have this type of pan, you fill from the bottom. Such fun. You'll need a fluid pump. There is a standing "spigot" inside the fill port that is open at the top, at the correct fluid height. You fill until fluid runs back out fluid to temp, engine running).
1. b. Nope. It won't fully drain the fluid/pan. See 1. a. above.
2. a. ZF say 10 seconds.
https://www.zf.com/unitedkingdom/en_...hange_oil.html
2. b. Keep your foot on the brake.
3. a. Nope - don't touch the 8mm plug - it has nothing to do with the fluid change. It's a port used to access an internal bolt (I think).
3. b. These are magnets that collect fine metallic particles from the fluid. They are mounted inside the pan - you'll see once you get in there.
Hope that helps..