So there's a rumor that Doomsday will be involved in the movie.
For confirmed and now rumored doomsday and previous rumors this makes the cast look something like
Batman
Superman
Aquaman
Wonderwoman
Flash (Rumor)
Cyborg
Lex Luthor
Lois Lane
Alfred
Martha Kent
Carrie Ferris (which could lead to a green lantern tie in)
Doomsday
Will feature both Gotham and Metropolis PD. Other employees of the Daily Planet, Lexcorp, Wayne Industries, has 2 members of Capitol City PD so maybe some scenes there (given the Flash rumor) Joint Chiefs, Russian embassador, a jail scene, a football game scene, and who knows what else.
Somehow they expect all that to fit into an enjoyable movie experience. With movies like age of Ultron and original avengers running at 2 hours and 20 minutes, and some saying that's too long. I have no clue how it can possibly work. Superman Returns was 2 and ahalf hours.