The Insteon Panel saved me. I was able to pair the mini remote through the Insteon Panel. Now it is back in the list, but I did have to restart HA before it showed up.
One more problem solved.
… time passes …
Then I worked on the Automation to get the remote to DO something. So I made an automation with a trigger, no conditions, and an action that was to turn on the light when the “f” button was pressed.
The key was to make the trigger be:
Trigger Type: Event
Event Type: insteon.button_on
Event Data: "address": "<myremoteIDwithNoDots>","button": "f"
… time passes …
I tried my second button automation. As I was watching the event trigger in developer tools, I could see that my new button was being pressed, BUT THE AUTOMATION for “f” was being triggered too. So that means that what I thought was the right syntax in the automation was not. Will have to play around more with that now…