You do not need to reinstall the FBA Pack for each of the zones. From your description you probably only need two zones - the extranet and the intranet. All zones have the same content. They are simply accessed using different urls + credentials.
If you make a page available anonymously, it will be available anonymously in all of the zones.
I did write a post on mixed anonymous and secure content in SharePoint, which might give you some ideas on how to structure your content:
What you probably want to do is have multiple sites - the root site in the site collection could have anonymous access and have the membership request and password recovery web part. Sub sites would not be available anonymously and would require the user
to be logged in.