I'm not sure exactly what any of that would matter. It's pretty much a given that most comic book shows and movies are going to have at least a few elements or characters the audience is unfamiliar with (by virtue of comics being such a niche media) so I'm not sure why Oracle not having a lot of mainstream exposure should preclude her from appearing. I mean how else is she going to get exposure if she's never used? Same thing for Hawk and Dove. They're weird choices to have ahead of more popular characters like Cyborg or Beast Boy (though I guess DC probably does not want Cyborg in it if he's gonna be in the Justice League movie soon) but if the writer has an interesting idea for them then by all means, he should go nuts.