What was the minimum age for EMM enrollment? J. C. Wyatt wasn't 18 until Aug. 1863 and we wasn't 20--the minimum age for draft registration-- until the war was over.
He does appear on a list of registered voters in the Oct 17, 1866 Daily Morning Herald--we would have just been eligible. If he was suspected of being Cave Wyatt, he wouldn't have been allowed to vote under Radical rule.
A Calvin Wyatt appears in the June 5, 1864 Morning Herald as a participant (actually as a "room manager") in a Strawberry Festival held by the Mercantile Library Association.