The Riddler's real name is meant to be Edward Nygma, and having a riddle-based villain called E. Nygma is a bit on the nose, so I can see why they changed that
though I always assumed it was an alias anyway.
With it being early in Batman's career, featuring the Riddler, and having Bats on a motocycle, it makes me wonder if it's gonna be a take on the Zero Year storyline from the comics.
The black kid is Duke Thomas, who then-writer Scott Snyder (no relation) really wanted to be the new Robin, but he wasn't allowed to use anyone but Damian Wayne... He was allowed to turn him into his own hero, called Signal, and he did wear a customised Robin outfit for one or two storylines though. With movies wanting to diversify their cast, Duke could be the movie's Robin?
On a similar note, I've never really given a crap about race-bending when it comes to casting, so Commissioner Jim Gordon doesn't bother me, but I really love Babs Gordon aka the first Batgirl being a redhead
in the comics she was originally adopted, and Jim's biological niece, so she could technically still be a ginge if they use her character.