About MP and bountys

A my first chars have reached level 30, i was wondering about these two.
Do I need a seperate char for mp, or can I use my singleplayer one for that too?
Are there any players in mp who are still playing on normal?
Are bountys repeatable or are they only available once per char?

  1. No, you can use any character in any mode at any time.
  2. People play in all difficulties.
  3. They are repeatable, but there is a limit to how many you can accept during one session. When you run out, you can just save and exit and reload the character to get a fresh new set.