Flash and Cyborg actors are in there 20s. WW and superman early 30s, Aquaman late 30s, Batman 40s. A nice range of ages and those have nothing to with there ages in the movie.
WW clearly the oldest.
Mamoa could pass as way younger if they want a younger Aquaman. Or older if they go that route
Cyborg and Flash will probaly be college graduate age
Supes and batman are roughly the age of the actors I believe.
Cast an older Hal Jordan or John Steawrt to balance it out