I asked GOG whether any of the tweaks they'd done for this release included the tweak to restore the hauntings that had apparently been disabled (but are present in the code, and apparently restored by one person) by a glitch. This is the reply, for info:
I'm afraid that GOG support is not the best source to ask about gameplay related questions. For such please reach the game's official support.
We are aware of the discussion regarding "hauntings" and we are investigating the topic. As for now we can't promise anything. If the GOG game will be updated we will provide update as soon as possible.
Bit of a nonanswer but it's something. What's the source on them being in the game's code but not enabled?