Thanks for your suggestions. By the way, 'skills' are only on Alexa, but I think I know what you mean. Anyway, I was able to get it all working by completely factory-re-setting my Google Home device...

Model : Hardware Version : Firmware Version : ISP : Hi All, Set up the HS100 on my Pixel 2, responds to voice (turn on/off) fine from phone. [*]Won't work from my Google Home device; says variations...