Hi raes and welcome on board! There is no reason why it shouldn't work? The flash shoe is the same, both lenses start at 28mm, so yes, I believe it will work with GX8.
I was just wondering if the eye relief would be too small, and if the finder goes too forward. I already have soviet made 35mm finder that looks like this http://www.dvdtechcameras.com/info/forum/11/8.jpg. It's working ok with 35mm focal length, maybe a bit too wide horizontally.
Unfortunately, I cannot comment the GV-2 eye relief, as I don't have this VF yet. I'm currently using the CV 28mm mini finder. It should be smaller than GV-2 but I have no problem with its size. I suppose, that the GV-2 eye relief will be even better? Maybe someone with both VFs can comment that?
The length of GV-2 should not be a problem as well. As you can see here..
(picture borrowed from this flickr)
..the GV-2 fits well with GRD body. So there should not be a problem with slightly thicken GX8 body?