We have no idea what's going on with The Flash movie. It currently doesn't have director or a release date but it does have a cast. Star Ezra Miller as Barry Allen will be joining the Justice League to punch some dudes this November and the trailers have already confirmed that Billy Crudup as Henry Allen will be making some sort of appearance as well. Model/actress Kiersey Clemons has been cast as Iris West and she confirmed in an interview with Modeliste Magazine that she will be making a cameo in Justice League.
This November, I'm making a cameo in Justice League as Iris West and it's the first time that you meet her before we get to see her in The Flash with Ezra Miller. It was my first time doing something so extravagant like that. We filmed in London and that's one of my favorite places.
It seems that a good portion of the supporting players for the various members of the league will be making cameos. From Aquaman (Jason Mamoa) we'll be seeing Mera (Amber Heard) and Nuidis Vulko (Willem DeFore). From Cyborg (Ray Fisher) we'll have Dr. Silas Stone (Joe Morton). From Wonder Woman (Gal Gadot) there are a lot of Amazons including Queen Hippolyta (Connie Nielsen) and Antiope (Robin Wright). For Batman (Ben Affleck) there is Commissioner Gordon (J.K. Simmons) and Alfred (Jeremy Irons). For Superman (Henry Cavill) we'll see Lois Lane (Amy Adams), Lex Luthor (Jesse Eisenberg), and Martha Kent (Diane Lane).
Summary: Fueled by his restored faith in humanity and inspired by Superman's selfless act, Bruce Wayne enlists the help of his newfound ally, Diana Prince, to face an even greater enemy.
Justice League will be directed by Zack Snyder and stars Ben Affleck, Gal Gadot, Jason Momoa, Ezra Miller, Ray Fisher. and Henry Cavill. It will be released on November 17, 2017.