On Steve Trevor, why would he be in modern clothes is he is a figment of her imagination? He would be dressed as she remembers him. I think he is there either magically or resurrected which is why he has updated clothes. It is going to be the reversal of Diana getting her clothes in the first film.
And I still dont buy the Brother Eye angle. Maybe if I thought it would be a plot point later (like Lex was using it in JL 2) but otherwise it honestly makes little sense and serves no purpose and is out of place in the setting. I get the "1984" stuff but still it is kind of a stretch. You are basically inserting Brother Eye into a story that he really doesnt belong. (where are the OMACs) And how exactly do they destroy him? He doesnt seem to exist in the modern films which to me is problematic. Plus the idea behind Brother Eye was to spy on Metahumans. Unless they are changing the timeline Metahumans arent widely known until Superman arrives.
When we finally get a trailer even more of these questions will open up. Oh the fun