I think I've caused some confusion. By outdoor ghouls I meant the ones above ground not in buildings. When I've encountered the bug, only the outdoor ones were still standing, whilst the ones in buildings where displaying the corrected corpse sprite.
As far as I know, all the ghouls will be dead, both above ground and below ground though I'm not sure if the underground ones are affected by the same 'still standing' whilst dead bug, its been a long while.
The ghouls in the vault are all still alive however, but they will have no interactions with the player other than becoming hostile if you dont complete the 'Fix the water pump' quest first, which can still be done even if the town is wiped out.