Which Justice League characters or which other DC heroes should cameo in this film?

I'd say Batman just because he seems to pop up everywhere, but...maybe J'onn Jonzz? Depending on whether this universe will use him.

 

Batman and Jordan have a great love/hate relationship. I don't mind a Batcave scene of some sorts.

 

Batman for sure.

 

I agree you can't lose with batman and I wouldn't mind a Superman convo with them hovering in space. I wouldn't mind that as an end scene with him seeing green lantern off, for whatever mission he'll eventually be on in his Corps. movie.

 

Whoops. Cameo in the Lantern movie. My bad. I guess then an end scene with Superman convo daying the league needs him because of whatever big bad is coming.

 

Wasn't that supposed to happen in the original GL movie script? ^^

 

I'd like a Supes cameo. Maybe after a big battle GL has beaten the bad guy but his ring's out of charge and he's pretty much stranded in the depths of space, when a familiar voice says "Need a ride?"

 

Maybe some Thanagarians.

I wouldn't want the movie to take place on Earth at all, and I think you could save JL members in space for a JL movie.