THE LEAGUE!
Henry Cavill as Superman
Michael Fasbender or Josh Brolin as Batman
Jamie Alexander as Wonder Woman
Which ever GL fits your fancy!
Chris Pine or Jensen Ackles as Hal Jordan
Omari Hardwick as John Stewart
Joseph Gordon Levitt as Kyle
Charlie Hunaham or Garrett Hedlund as The Flash
Body of Doug Jones and voice of Idris Elba as Martian Manhunter
Alexander Skarsgard as Aquaman
Stephen Amell as Green arrow
THE LEGION
Mark Strong Or Michael Fassbender(if not bats)as Lex Luthor
Giovanni Ribisi as The Riddler
Kerry Washington as Cheetah
Sebastian Roché or Mark Strong(if not lex)as Sinestro
Aaron Paul as Captain Cold
Body of Derek Myers and voice of Kevin Grevioux as Ma'alefa'ak
Djimon hounsou as Black Manta
David Tennant as Count Vertigo
And just for fun..
Ryan Kwanten as Booster Gold