Still too early to say, but I think ghosts are certain. Group events probably won't be in the initial version, but almost certainly in later updates.
That's a game I actually have a pitch picture for. It got second place in the last poll. There are a few changes planned from the initial concept that I describe in the illustration. Most notably, the game's perspective will now be focused on building rooms inside the castle itself rather than developing the domain. Other than that, the attached illustration is sort of still my plan for that game if it gets picked.