1. What other parts depends on the condition of the pads, drums, springs, cylinders, etc. Was the system working correctly prior to this?
2. New one should bolt in.
3. Yes, correct.
4. Which lines go where will become evident when you start swapping pieces in. All will line up when you get there. You'll have to bend, massage, etc to get things to line up just right.
5. Yes, and the new MC should come with a new push rod rubber seal. Put the old MC in a vice, attach some vice grips to the push rod and pull. Angle it downward a little you can use gravity.