I don't think you are finding content on the web because these are not the standard use cases for these features. Wikis are collaborative in nature, and made to able a bit open, though it may only be open to contributors of a given audience.
If you are looking for publishing capabilities, then you should look at the publishing features and identify an appropriate page layout.
With regards to permissions, weather it is a wiki or a publishing site, you can configure them as individual sites and then set the appropriate permissions on the site as there is no clean way to secure an individual category. Any page can be tagged with any category in the enterprise wiki.
An alternative suggestion would be to setup to receive change notifications so that they can perform as a librarian to ensure that things are filed in the right spot and that inappropriate content is not displayed.