Why try LibreELEC-X8-X8H.arm-9.1-devel-20190310183315-782f78e.img on X8-H Plus ? did't even know that would work ...
Did you try the LibreELEC-X8-H_Plus.arm-9.1-devel-20190311010121-555ace9.img ?
You're right, I copied the wrong link into my post. I tried "LibreELEC-X8-H_Plus.arm-9.1-devel-20190305230841-782f78e.img" -- wifi was working for me on that one, but no InputStream addon and LibreELEC repos didn't function.