So quick update... and I feel rather dim. After swapping USB cables, trying debugging mode, reinstalling the Android Auto app, got rid of hondalink, rebooting everything, played with diagnostics mode, tried a different phone, LOTS of internet searching... I used Settings, Smartphone, Android...
Nexus 6p is my main phone. No custom rom. Just validated that it connects to my computers just fine. Later on today I will be checking the phone without hondalink installed and a 2nd phone that's running an older custom rom with debugging/security tools installed. We'll see what happens.
I wish I could say that same. It worked great... for three days. Now no more Android Auto. :( Troubleshooting information is very sparse on the internet so it's been rough going, still haven't found a solution yet. When it work's it's great. Without it, it's sad times. If anyone has...