Hold Me Closer, Necromancer is a play on Elton John's pop hit "Tiny Dancer". Obviously, the story doesn't have much to do with the 1970s or Elton John. Still, McBride's decision to parody the song in her book's title points directly to the story's darkly satirical nature. Making a connection between a feel-good 70s classic and necromancy is about as comedic as the links between necromancy and the real world that create so much of the book's humor.
Is there a chance that the title could also be referring to Bridin and Sam's relationship? Sure, but it's more likely that it is simply setting the tone for the book's paranormal dark comedy.