I read the title, then I see it's in Nintendo section.

I click with high hopes. You're not referring to NX rumour threads :(

I always thought of the Ghost type Pokemon of the game to be more like the Ghosts of Casper the movie... sort of like Pokemon who died but hadn't moved onto the after life for one reason or the other, the Marowak who died protecting it's cubone from Team Rocket in Red/Blue so she stayed there to mind the Lavender towns tower. Or the way it appears the original Trilogy of Ghost Pokemon appear to not want to move on so they could cause mischief not unlike the 3 uncles in the Casper film again.

My thoughts would be when a Ghost Pokemon has finished its time being a ghost... it moves onto the afterlife where it joins the other Pokemon who died and went there directly.

Same!

Anywho, I believe there were ghost types in the AZ war, and I don't recall if there were many if any survivors, so the ghost must have died all the same.

Uh, don't worry about it

Wasn't the Marowak in Red/Blue/Yellow pretty much exorcised in a sense?

I look at threads through the "Latest Topics" tab. So I had no idea what section it was in when I clicked. 

If they don't die  I will do my best to change that..

Not so much die but move on to another stage of existence, think of it like the water cycle or don't think of it at all. I doubt anyone at Game Freak is. Otherwise how could they explain how a ghost pokemon can be born or Cubone exist on the same team as his mother Marowak.

NX was delayed from 2016 so Nintendo could figure out the answer to this. It makes perfect sense.

My clicks are faster than my tought... not that my tought is very fast either