>>18989600Aegislash needs to be on the team. That is not up for debate.
Jellicent, Chandelure, and Gourgiest-Super make for a spooky FWG core, which is nice I guess.
Sableye might be able to pull some useful shit with Prankster. It also keeps your entire team from being weak to Dark and Ghost.
Finally, Golurk is... workable, I guess. You might want to use Cofagrigus here, but it's important to remember that Golurk is the only Ghost-type Pokemon capable of learning Stealth Rock.
The name of the game is Trick Room. Your goal is to strike hard and "last" with the stupid-good coverage of Ghost-type STABs. How you make that happen is up to you; I have no experience running TR, sorry. Still, this is probably your best shot for mono-Ghost right now.