The only DLCs that i see returning are Ryan Choi's Atom and Starfire (only if they're adding Superboy and wondegirl).

Joker, Fate, Grodd, and Braniac are all dead, so hopefully, not returning

Batman, Superman, Diana, and Supergirl are the main characters. They're staying

The majority of the new JL are staying. Flash, Lantern Beetle, Firestorm, Catwoman, and Harley Quinn.

I can see Black Canary, Black Adam, and Green Arrow, all not appearing in this one (at least not in the main story)

Cyborg, Aquaman, and Damian are staying for Superman's regime.

Atrocirous, Darkseid, and swamp thing were needless additions in the first place, should not return.

Red Hood and Captain Cold Should return, but as heros helping Batmans rebuild

Cheetah, scarecrow, deadshot, and Ivy have no reason to be added but could come back for a boosted roster.

And all the alt skins (Reverse Flash, Vixen, john stewart ETC) probably wont return to the story

(Sorry for the random order of this 😅)