Fan Casting "The Batmen of Infinite Earths" in Matt Reeves' The Batman Beyond - Part III

At the end of the movie, when Matt has now become Nightwing Beyond and Terry has managed to extend his version of the Batfamily, he, his brother, and all his Batfamily Beyond members are suddenly transported through time and space. The group then find themselves being recruited to help not just one.. But multiple variants of Batman.