I was finally able to get the linking working between Google Home and Rachio by the following steps:
- Using my wife's iPhone instead of my Samsung S7 Edge, as the linking never completed on the S7 Edge.
- When using my wife's iPhone, my account was signed into the Google Home, so that the Rachio would associate my name and voice instead of my wife's name and voice.
- Once linked, I signed out of the Google Home app on the iPhone, and signed into Google Home on my S7 Edge.
- The Google Home recognizes my voice and I'm able to talk to Rachio via Google Home.
So, bottomline, if you use an iPhone, the setup works well. If you use an S7 Edge, the process never completed for me.