This is the same gen with Sensu Oricorio and Alolan Marowak in it.
http://www.pokemon-sunmoon.com/en-us/pokemon/oricorio-sensu-style/>The Sensu Style Oricorio is quiet and collected. By means of its dance, it gathers the spirits drifting about in an area and borrows their power to fight. http://www.pokemon-sunmoon.com/en-us/pokemon/alolan-marowak/>It’s said that their great care for their partners allowed them to gain something like a sixth sense and resulted in their changed form.It's now been established that Ghost-type Pokemon don't have to be literal ghosts; they can just be Pokemon that have some sort of sixth sense or channel the power of spirits; which Decidueye does with its signature move, Spirit Shackle.
