This is a fairly low effort means to dealing with these 3 (and possibly more) challenges. (provided your doing prestige perks and such as your waiting for lvl 200)

What you will want to do is get the attacker helper up to about LvL 200.

Going as far as you can (not necessary but probably a good idea) with out the helper you want to then cloud save, then exit. The time that steam takes to synchronize is enough that when you enter you can level the attacker helper up at least once. From there the helper will take care of all necessary ten stages of the challenge.