This plugin displays the author profile at the end of the post. There is the option to display the author's user profile or a custom profile.
Any custom author will take precendence over website users. So the custom author will be displayed.
No, if a profile user is disabled in the user settings, then no custom author will be displayed. The only exception to this is if you have a custom field in the post for "post-author". In that situation, the custom author specified in that field will be displayed.
Create a custom field in the post for "post-author" and put a non-existent username in there (e.g: nobody).
The plugin works using the following logic:
Find out more at http://littlehandytips.com/plugins/custom-about-author/
A handy plugin from little Handy Tips :)