Ben Affleck has at least three more movies as Batman before DC will even consider replacing him. Josh Brolin is not in the running for Batman. Not only is he contracted for three more movies as Cable, but you left out his other big role in the Marvel Cinematic Universe... Thanos. Joe Manganiello is already part of the DC Universe as Deathstroke, so he's not going to be playing Batman.

When "Phase I" of the DCU is finished (after Justice League 3) they'll probably recast most of the main roles before they move on to the Legion of Doom phase.