WHD wrote
yes, the three individual ghosts are also three individuals in real life.
Lisa is not one of them, the author of the attacks is.
Is one of the remaining two the one with a superpower?
Do the three know each other?
Is the author of the attacks aware of Lisa's dreams?
Are the attacks actually part of a ritual?
Are the attacks actually random?
Did Lisa dream about those attacks?
WHD wrote
Somehow, her dreams sometimes become reality
If she didn't have those dreams, would the events still occur in the reality?
Are the dreams messages created by someone who knows some events are going to happen?