Right, kwho-user will make them all blue. I don't understand what you're trying to do. You want them all black text? Please be more specific. The below are the classes you can use.

kwho-admin = bright red
kwho-globalmoderator = deep red
kwho-moderator = bright blue
kwho-user = light blue
kwho-guest = gray

You can of course supply your own class such as the following.

With the above you'd use "kwho-custom" instead of "kwho-admin" and the text would be black.

You can't use Kunenas dynamic coloring when using Advanced because you're completely replacing the sidebar. You'd need some sort of IF substitution to check what type the user is and change the class based off that. IF substitution information be found within tutorials in my signature.

No, the Advanced textarea supports substitutions; for example [username]. You'd need to use an IF substitution and check for example what their gid was (usergroup id) or usertype (Administrator, Registered, etc..) and try to color them based off that. More on substitution usage can be found within Tutorials in my signature. PHP sidebar and using Kunena API is best way to have what you're wanting, but if you've no PHP knowledge it's not going to be possible.