I am not sure I understand the question, but will try to explain further:
They don't appear on my lot, from their urn/gravestone, like they used to - they appear in the open neighbourhood area instead. Except for the one in the picture, I have always found them stuck in the spots where NPCs appear/fade out when they jog etc in the neighbourhood.
It is only the ghosts belonging to the household I am playing at the time, that appear in the neighbourhood. Not the other ghosts with urns on other lots (unless I am playing one of those households). And they don't appear in other areas like community lots. Unlike all other played, but inactive sims, they have never been used as normal NPCs by the game. They used to just appear at night, when playing the lot the urn is placed on, and act as uncontrolled sims, but always staying on the lot. When I notice them stuck now and use resetsim, they come back to the lot and haunt the place as usual, until morning, when they return to their urns.
That ghost on the side walk is stuck in a spot outside Brook Bungalow, that I don't normally think of as a spawn point, although the Brook Bungalow household will be standing there when I load that lot. In this case, I was playing the lot on the upper left corner of the picture (sorry, the lot has been renamed, and I don't remember the original name), not the lower right corner lot that the ghost is stuck outside.
My save game has 7 ghosts, in 4 out of the 30 played households. The 4 houses with ghosts are in 2 different neighbourhoods in WC. All 7 ghosts are having the same problem: They don't appear on the lot, but in the neighbourhood, and they are all stuck until resetsim is used. I rotate daily, so I don't know if resetting once would make the ghost work properly until the next time you leave the household, as I have always swapped household before it is time for their next appearance.
None of the ghosts have been added to households, or otherwise played as ghosts. They are simply dead of old age and left to haunt their offspring.