1-I would think he can indeed charge lillith even if he does not move to do it. The rulebook defines mele range only against enemy models and not frendlies
2-you can charge in any straight line you want so yes you can charge Lilith and place yourself in such way that you can strike Lady J, your charge is still against the closest model, in that case, Lillith.
3- KillJoy drops 3 corpse counter, that s why I don't mind him dying so often from enemy focusing on him.