Looking for a method to display user role as an icon

You can still apply similar code, just that the user ID may come from somewhere else besides the $comment object, depending on how the particular template is setup. If you have several roles, you could use a switch/case structure instead of a simple if/else structure.

To style the username, apply the same logic, except instead of echoing an img tag, echo a span tag of a particular class. Add CSS to style that class how ever you like.