Ezra Miller’s Flash could still be replaced. Yep, in the Multiverse nothing is off the table. Hear me out. Ezra is… well something is up with him. It is something that makes the suits at Warner Brothers uncomfortable. Heck I am not sure I’d want to hang out with him. I really started out as a fan of his work. Now, the optics of his activities are not the best, and they seem to be getting worse.
Enter Grant Gustin, the CW’s Flash. For multiple seasons he has been a rock. His acting is steady, and his portrayal of the scarlet speedster is a joy to watch. Writing Ezra out wouldn’t even need to be a big deal. Add a ripple effect and Grant is there to finish the rest of the film. Dapple in some glitches in Ezra’s finished scenes, here and there, then have a bit of exposition about it. I’m not a writer, but this is just a high-level view of a plan.