Superman confirmed to be a reboot.

[Professor S]

Superman shouldn't be dark. Thats the fun of Superman and Batman. They are the opposite of two coins. The way a Superman vs Batman film would work is if they are opposites, but you could see both sides.

As for Lex, they should base him on his "Man of Steel" one shot, where much of his hate for Superman is explained, and even intimates a relationship between himslef and Bruce Wayne.