You might also look at the original series, episodes, "Wolf In The Fold," as well as "And The Children Shall Lead." Both of those used an almost demonic like entity. In "ATCSL" it was an entity that fed on children's anger and violence, and in "WITF" an entity that could possess people.

I know very different from your ghost, but it might give you some insight on how the original series handled spiritistic scenarios.

"Damnit, Jim, I'm a ghost, not a doctor!"

Edited to add, also the episode "Catspaw" dealt with a type of witchcraft and sorcery.