WordPress.org

If I have both a custom author and a website user with the same username, which will be displayed?

Any custom author will take precendence over website users. So the custom author will be displayed.

If I have chosen to disable display for a profile user, would a custom author with the same username 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.

How do I disable the display for just a single post?

Create a custom field in the post for "post-author" and put a non-existent username in there (e.g: nobody).

How does the plugin work to determine whether and which profile to display?

The plugin works using the following logic:

1. check if author has disabled display
2. check custom fields "post-author" to see if an author is specified
3. If author has disabled display and there is no valid author specified in (2). then nothing will be displayed.
4. Otherwise check if author has a custom profile
5. If it does, display custom profile, otherwise display user profile

Find out more at http://littlehandytips.com/plugins/custom-about-author/

A handy plugin from little Handy Tips :)