There won't be any multiple endings.Well, since this game would have only one playable character, 'nuff said.
Aiden is the ghost of a member of Jodi's familyIt's the most obvious guess but someone had to say it.
Jodi was involved in some sort of secret government research...as a test subject, and now they want her back. This one goes to Quantic Dreams' previous incursion into the conspiracy genre.
Jodie will not be the only person that can see Aiden.Perhaps at some point in the game there may be a particular person who can see Aiden for various reasons.
Aiden is Jodi from a Bad Future, come to Set Right What Once Went Wrong by protecting her past self.
Aiden isn't a ghost or person from the future, but is actually an evil entityThe game is confirmed to deal with the afterlife. But nobody ever said that Aiden HAS to be a spirit of some sort. He could very easily be some other entity trying to gain Jodi's trust for an ulterior motive.
Aiden's human form is
Norah Gray kept her maiden name