The GH4 mount is protruding a little bit more on the picture you post, the G80 mount is more flat and the evf housing seems lower, argh :/ No reply is possible (problem) on the comment section under the article. I will try to mail Luke Massey, or maybe via his youtube channel : https://www.youtube.com/channel/UC_2mvU6hq3J1bW4qEIas-Jw/videos his videos with the G80 are cool, too bad if even Metabones site says it will not fit, maybe it's too soon, idk.
How is the G7/GX85 camera structure comparing with the G80?
Edit : G7 vs G80