I'm not so sure. I think Nolan already used aspects from Dark Knight Returns in Rises. Bruce's retirement, his abrupt return (and using an old and young cop to highlight that came directly from Returns), and the way the film ended, I don't think it sets up a Dark Knight Returns situation. I also can't see Catwoman in a Justice League film. A Birds of Prey film, yeah, but not the Justice League, as member of the League.