In EW's latest issue covering Comic-Con, it's noted in their Batman Vs. Superman article the Justice League script is ready.
Here's the blurb:
To craft the costumed-hero mash-up, Snyder and Chris Terrio -- the Argo screenwriter who was brought on to Batman v Superman for a rewrite and who has since finished the Justice League script -- locked themselves in a room with an enormous supply of Diet Coke and plotted out their epic saga visually, like a giant cave painting. "Chris would talk and I woud draw and it was basically this weird mural of the movies with no words," says Snyder.
They drew from their own imaginations as well as comics mythology, including Frank Miller's revered 1986 The Dark Knight Returns, which also posits and embittered Batman past his prime setting his sights on our boy in blue. In his editing suite in Pasadena last month, Snyder showed off early passes of the money sequence, a rainy rooftop battle between the two capes. There's an undeniable thrill to watching these pop culture icons go at it -- that can likely be traced back to a memory of lying stomach-down in the living room, an action figure in each hand.
"Justice League Part One" has a 2017 release directed by Zack Snyder starring Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ray Fisher as Cyborg and Amy Adams as Lois Lane. "Batman v Superman" hits March 25, 2016.
Batman Vs. Superman Trailer: