The joke was that Zim would successfully kill Dib, and his replacement would also have a paranormal obsession.
Other than the above information, little is known about Louie. So far, no character designs have been released, and because of the character never being used, it is also unknown who his voice actor would have been. As a result, several fans have incorporated their own designs and characteristics for Louie.
There is a chance that Louie was named after storyboard supervisor Louie del Carmen.