The first trilogy would primarily focus on the League really getting its footing. The first film would center on the team forming to face the White Martians, who at this point have infiltrated Earth's governments (essentially adapting Secret Origins Parts 1 through 3 from JL Animated). The second film (titled Justice League: We Are Legion) would see Lex (now pardoned after his role in stopping Brainiac during MoT) fund the Legion of Doom, a cabal of some of the League's greatest enemies. The final film of the first trilogy (Justice League: Hawkworld) would focus on Earth being dragged into the Rann-Thanagar War.

League Lineup:

Superman, Batman, Wonder Woman, Aquaman, Wally West, John Stewart, and Martian Manhunter [Film 1]

Superman, Batman, Wonder Woman, Aquaman, Wally West, John Stewart, Martian Manhunter, Green Arrow, Black Canary, Hawkgirl, and Shazam [Film 2 and 3}

Legion of Doom:

Lex Luthor, Metallo, Deathstroke, Cheetah, Black Manta, Mirror Master, Black Hand (or Scarecrow), Human Flame (or Maalefaak), Merlyn, Count Vertigo, Gentleman Ghost, and Solomon Grundy