Hi ! The GF ghost should still be available, if by that you mean the Blue ghost. For the issue with the ghost going at the edge of the screen, we realized the issue a bit late after release. It is due to the window size on Windows. We'll fix that on next release, in the meantime, if you set the window size to avoid the black bars on top or on the side of the screen, the ghosts will stay in the game area :-)
known mistake? even in the demo version you have to provide such details, there was no mention of it in the entire description, you mention it only in this comment, I had to figure it out myself at the very beginning when I was playing the game, I encountered many errors in the games but never one like this specific.
I don't know which Blue ghost is (horns I guess, they are named only in gallery), but you shouldn't remove this ghoul in first because all the ghouls will go outside the map in the Windows version.
and from what I see on the screenshots on the website, there is one photo of a ghoul which clearly shows an ghoul girlfriend.
a small detail that caught my attention was calling the main protagonists sometimes ghouls and sometimes ghosts (a ghoul and a ghost are two different things that the only thing they have in common is a cemetery).
so I predicts all of these bugs will be fixed in the official released version, at least I hope so.
all ghouls go to the edge of the screen except the plant and the spider because they move too slowly