You know with work and all I think I'll hold back anyway. Flash and Grodd are p evenly matched plus J'onn's there.

That said I think the general idea was, "if they're unplayed just NPC them and don't break anything you don't own.". Work them into the narrative of posts. You can also always use minions, Grodd's pretty good at hechmen, gadgets or other devices to even the odds.