oh shit youre right he is in it, maybe he has to do with all the heroes disappearing and the crime syndicate showing up, this is gonna be really interesting id wager they probably all end up on the parallel earth (earth-3 i think) and Dick being the only one staying
Well from the interview Johns gave, he said that it was specifically the Crime Syndicate invading the regular Earth Prime to take it over, and that since our heroes are gone (except for Batman apparently) from Trinity War, the villains step up to fight them from ruling.
I was never aware Wonder Woman was stronger than Supes. Could be because I only just recently started reading more from her. I just remember that one episode of Justice League where Mongul put that plant on Supes and WW started fighting him. She was having trouble near the end but then Superman beat him proper. Maybe artistic license. I don't know.
I can say for a fact though that Martian Manhunter could absolutely defeat Superman is he had to.
Wonder Woman isn't physically stronger but she's close to his level, is just as fast, can fly as well, and is a much much better fighter than he is. Plus she has mystical weapons that can all harm him, unlike most things. So that's why she's capable of doing it. It's not like she'd crush him or anything, it would just be very plausible for her to win, as much as it would be for him to win. Same with MMH, in my opinion, but J'onn has an even greater advantage with his telepathy.
And yeah that episode confused me because there was an earlier one where she and Superman fought and she was at least holding her own against him because they both saw each other as demons from this magical trap they'd gotten into. But yeah, it was adapted from a famous comic story that was older so maybe that had something to do with it.