Apple USB-C Multiport adapter bricked
Your adapter is not bricked per se. I have two of them and have been unable to get them to work at all under Sierra 10.12.6 using HDMI. I was able to update them both and reboot successfully. They both show up under System Information as you describe, but no connection is ever established with the HDMI display.

Failing the reboot of the computer is not the problem. It's just that the reboot is needed before the system will recognize it. If you have rebooted since then, you have done all that you can do. I have thought about reaching out to Apple Support, but feel it is going to quickly become a wild goose chase with them.