Although there were only two Capcom Ghosts releases in the world of Nintendo (Ghosts 'n Goblins for the NES and Super Ghouls 'n Ghosts for the Super NES) I cannot help wonder if Capcom could've released the original Ghouls 'n Ghosts for the NES? It would've benefited from their sound library they'd used in their other 1989 NES releases such as Mega Man II and Disney's DuckTales.
I'm led to believe they never did so for the NES, since Nintendo's main competitor, Sega, had already self-released Ghouls (under license from Capcom) for both its Genesis (1989) and Master System (1990) consoles.
Of course, all three of these Ghosts titles are different. Of the three, only the Super NES release, Super Ghouls 'n Ghosts, was never released in arcades.
~Ben