Here's a pretty major clue towards the ghostly threat in the film that directly points to there being much more going on than we're seeing here, yet seems to have been pretty much ignored: there's going to be time travel in the movie. In the wide shot of the gang in Times Square with various ghouls swirling around, the massive adverts mystically transform from the very present to the past, with big Twinkies, Papa Johns and Blu-Rays (because Sony learnt nothing from The Amazing Spider-Man 2) making way for neon signs and movie posters for Isle Of The Snake People, Taxi Driver and Tommy (movie's released almost a decade apart, but pointing towards this being the seventies). There's nothing else from this sequence to build up a coherent theory on - this could just be the "ghost" of New York City emerging as a part of the villain's plot to amplify paranormal activity, serving the plot in no direct way - but it does open the door for some fresh ghostly action.
