How to resolve error Font-awesome library could not be found? For some reason my Drupal 8 installation is issuing this error after I installed and enabled Fontawesome (via the commerce module).

I don't know 



I think this is the dir it is asking me to check, but all seems fine
You need to download FontAwesome and move files into the /libraries directory. It is explain in the documentation of the module here

And you had a clear warning message explaining that. You could have read the README.txt