One question that seldom gets discussed, but presents an interesting dilemma, is when the SHAZAM! franchise should make its first entry in DC continuity.
Pre-COIE, it was relatively easy: the Golden Age Fawcett Comics SHAZAM! adventures took place on Earth-S during the 1940s, as originally published, but had no contact with the rest of the DC Multiverse until the 1970s, when Captain Marvel and his cohorts first began crossing over with the DC heroes of Earth-One and Earth-Two, etc.
Post-COIE, it appears as if the SHAZAM! franchise was entirely absent/nonexistent until shortly before LEGENDS: in other words, Captain Marvel, et. al., would not have participated in the First Crisis or any adventures that took place before that point in the Post-COIE timeline. Like the Wonder Woman of that continuity, Captain Marvel was a newcomer during the timeframe of LEGENDS and had never encountered Barry Allen's Flash (who had died before Billy Batson gained the Power of Shazam) or Dick Grayson's Robin (who was already Nightwing).
With the New 52 and REBIRTH, the waters have become muddied. What is the status of SHAZAM! in current continuity? When did Shazam's career begin relative to Superman, Batman, Wonder Woman, Flash (Barry), etc.? Did he begin when they did (highly improbable, because Billy and his friends remain children/adolescents) or just recently (more likely, but this pretty much keeps Shazam awkwardly stuck in a perpetual status quo of being a newbie hero)?
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