Not sure if this qualifies as spoilers, but WOW!
That raises a lot of questions:
1. Who is Sarah? Sarah is having another what? Baby, vision, seisure, what?
2. Is the thing shapeshifting as Harper a conglomerate of people (WE, save US) ? Is Jacob a collective ghost? The ghost of the pirates or an earlier one?
3. Why do they call Juliet "The other woman"? If she is the other woman, who is the first one? If she isn't, who are the women reffered to?
etc.