Really unique idea and fun game, there is one thing that's a bit broken not as in that it does not work properly but that's completely overpowered and it has to do with how the level is presented/starts (@dev check below the "Attention" line, meant to prevent spoilers).
Also, I'd like to suggest maybe some sort of cooldown for the ghosts, i know there kind of is, but i think it's too short specially for the ground ghost.
Cheers, and i hope this helps! ;)
Attention: do not read below if you haven't played the game yet.
Since there is only one entrance to the cemetery and the characters are there when the player gains control, you can just put a ghost in the next ground tile and you could potentially scare both of them out of the cemetery with a single attempt. It took me two attempts but only because the girl stopped at the very edge of the map. To solve this, i propose a "observation time" at the start where the player can't still use ghosts, and the NPCs use that time to spread around or go to designed positions.