Aquaman, Shazam, Black Adam, MMH, and Doomsday have already been confirmed to at least appear in story mode and I think pretty much all of them are shoe ins given where the plot (the primary character decision) is going.
Batgirl, Powergirl, Penguin, Supergirl, Swamp Thing, Animal Man, Batwing have only ever been teased as shit lying around on Boon’s desk. So either they’re all in / planned for dlc, or none of them are. Either way, I wouldn’t hold your breath.
Lobo has been basically confirmed for DLC, and so is anyone one else whose plot neutral, cosmic, or otherwise unrelated to metropolis / gotham.
And Blue Beetle and Raven (and Zatanna and Red Hood, for that matter) were never teased or anything, fans just cling to them because they got mentioned in casual conversation with staff members.
Either way, even if you plug in everybody known then add all the story mode confirms you still have 4 (or 5 if doomsday is unplayable) total wild cards based on the 24 character select screen shown thus far. Those are pretty good odd for some random / unsuspecting characters sneaking in.
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You don’t like the dev, or what the game looks like, but you’re still paying attention? Thats insane, but regardless not only is this NRS standard operating procedure and their consistent blockbuster sales numbers give them no reason to change, but MK9 was literally leaked to death almost a month before release, and not like some sketchy lupinko report on some dark corner of neogaf, no, SRK posted the entire goddamned character select screen front and center on their front page as did several other sites. So if anything, they’re probably just paying us back.
Edit: Oh shit, I forgot about Cold. But even so, that gives pretty much everybody revealed a villain of their own, with 3-4 spots left to go.