For the unfamiliar: The Silver and Bronze Age occasionally published "Superbaby" stories, about Clark Kent's misadventures as a preschooler learning to properly use his powers. As for his superhero-ish clothes, it's a "playsuit" made of his invulnerable blankets.
@timrichards guess since there's a "JLA" on Earth-C Minus, there's probably a Spectre-analog there (or an Earth-2 equivalent). But otherwise, they haven't shown or mentioned one AFAIK.