Once again, my thoughts are:
The Juno Eclipse we see is a clone or a robot because she survived that fall. "As long as she lives, I control you." (or something like that)
The Dark Apprentice is somehow the real Starkiller and he's just being controlled by an elaborate hoax. The good clone was created on purpose to get him to "kill" his good side. "Maybe he's here."
Obviously I have no concrete evidence whatsoever.