For step 3. Warlock void abilities count. The peek of making an enemy explode from your ability counts too. So grenade one enemy and get the kill, it exploded and killed another? 2 kills. Same for melee ability. It counts as long as it's charged. Obviously the nova bomb counts. Also, of anyone wants help for the last mission on hard (lvl 30, you get 5 more of light) I'll help. I'm a lvl 30+ warlock, GT: Yajuu Omoi