I don't know if this is a glitch or not, but I was able to snitch a gravestone from the graveyard. This is in my game where I'm trying to get a Sim married to a ghost. I found a ghost who has at least three traits that are the same as hers(I don't know what his last two traits are). While mousing over the graveyard, I clicked his headstone and found I was able to take it. Ezmyrelda isn't a klepto, so is this a glitch, or just something I've simply never known about? I plopped the headstone in Ezmyrelda's yard, so now she has a drowned ghost haunting her lot(and amusingly, next-door neighbors).
Even if it is true you can't marry NPC ghosts, at the very least, I want her to try to have a kid with him. I've never raised Sim kids, so I think it's about time I did.
I laughed so hard, watching Ez have a conversation with a ghost about gardening.