Definitely. The JSA is already stacked with magical heroes. The JSA is also stacked with teenagers/young adults. Billy and Mary Batson, Courtney, Jade, JJ Thunder. Raven wouldn't be out of place. Plus, Raven brings her own rogues from the TT to the JSA. Trigon, Brother Blood, Phobia, and Jinx.
I'd add Pandora as a recurring influence on Raven and Billy. Pandora can see and is menaced by the Seven Deadly Sins. Raven's empathic abilities and being Trigon's daughter gives her insight into the wickedness of others. Billy's job as Shazam is to keep those sins in check.
Add in the Phantom Stranger and have him send Raven, Fate and the others on an impossible quest.
Take the mystics to Gemworld. Fight the cancer that is Mordru is the past, present and future (old man Legion of Superheroes version).
Skies the limit really.