Both Martian Manhunter and John Stewart have been announced for the well-received fighting title Injustice: Gods among Us. Both characters were revealed at the Evolution Championship Series. Voice actors from the Justice League animated series are back for both characters. John will apparently be a skin for the current Green Lantern (Hal Jordan) while Martian Manhunter will be a brand new character.
And for those who may have missed it Earth two Hawkgirl Kendra Saunders is also available as a DLC Skin for the standard Hawkgirl.