In the end..

[Ryan Nowell]

Will we be able to play as all 8 characters in one game And Greif Mode was a test to see how all that would go? o.o

[Flammenwerfer]

Have you ever played a glitched 8-man TranZit game? I did once and it's crazy.

IF they did a co-operative map with all eight, they would have to make the map actually big. Think Green Run but with actual PLACES where the long stretches of road are.

I honestly can't see that happening, though. Maybe a special Grief Mode that's non-canon and features both groups, but for now, I wouldn't hold my breath for it.