I want to throw out he idea that Sarah is on the island. I mean, I'm pretty sure that Zeke/Tom guy was in a hospital bed at Jack's hospital and Jack was taking care of him. If Tom is there, couldn't Sarah be on the island? All of the stuff that Juliette says she knows about Jack is just background check material, but knowing if someone is happy or not wouldn't be included. Either she is making it up, she knows first hand, or they have like supernatural powers or surveilance techniques. Like sattelites.