Early in his caped career as Captain Marvel, he learned that the young boy who was connected with him was only one of four lads named Billy Batson. While facing his arch enemy Sivana, Cap discovered that Fat Billy from Brooklyn, Hill Billy from the southern United States and Tall Bill from the western part of the county can call upon the same source of power to transform themselves into Fat Marvel, Hill Marvel and Tall Marvel respectively... each possessing superhumanly powerful bodies. Assembled they are the Lieutenant Marvels, and alongside the Captain they were also charter members of the Squadron of Justice. They would periodically join forces to aid the Marvel Family, as would another honorary Marvel in Freckles Dudley.
The older Lieutenants' contemporaneous counterparts on Earth-Two would be the three members of a Patrol consisting of Slim, Fred and Pedro who most key operate out of Europe for the duration of World War II before coming to America for a post-war career as she superhuman protectors. They would be aided by Norah Blaine, who like Freckles was a fearless female even without powers of her own. And both of these teams also mirrored the Doom Patrol of Earth-One, who had radically transformed Rita "Elasti-Girl" Farr, Garfield "Beast Boy" Legion Logan, and Larry "Negative Man" Trainor... aided by their handicapped benefactor Niles "Chief" Caulder. And just as both Patrols had Robotman which they were associated with, an honorary member of the Lieutenant Marvels' Family was the robotic Shazam Robot that Uncle Dudley Marvel created.
As for the three younger alter egos of the Marvels, the three Billy Batsons from Brooklyn, Tennessee and Texas, were dopplegangers of the trio of crimefighting crusaders known as the Blue Boys from Earth-Two. That team, correlating with the Batsons, were their leader Little Boy Blue aka Tommy Rodgers... Tall Billy's twin, Blue Boy Tubby's twin of Fat Billy, and Blue Boy Toughy's twin of Hill Billy.
Earth-One would likewise have a team of Teen Titans in Mal Duncan aka Guardian, as well as Hank and Don Hall aka Hawk and Dove. The Marvel Family was the preeminent protectors of Earth-S, whereas the Titans and Boys were second fiddles to the adult teams of their respective worlds.