Please read carefully before respond
when you activate font awsome via
Theme Options > Speed optimization > FontAwesome Support
only the version 4..7 will work because of the code added in walkers.php file
default: $icon = '<i class="fa fa-' . $icon . '"></i>'; break;
please romove it so the other 5.x version of font will work
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.