Fan Casting Cosmic Boy in Captain Atom 2: Legion Of Superheroes

Is the current leader of the Legion and isn't initially keen on enlisting Captain Atom to help with fighting Braniac in this time. Encourages Atom to not reveal what he has seen in the future but warns him of Savage and to try and guide the Justice League in his time as subtly as he can as well as Earth's allies such as Waller. This is to avoid changing anything that the League needs to do in the present. However Nathaniel may not need to but he might talk with Superman but only if necessary. So if he works out that someone in Secret Society movie is pulling all the strings then that might be the time?