...Follow me on this: what if...
spoilers:end of spoilers
... Cole ends up being a willing host for the possession by Hanzo’s spirit, or a reincarnation that allows Scorpion to manifest? That way, you get to make scorpion be something like a “special guest” character?
Perhaps Bi-Han killing the original Hanson/Scorpion should literally mean that a ghost can’t just enter and compete... but there’s a loophole involving rebirth.