WordPress menu with custom taxonomy

Maybe for the next time, create a question for each topic 😉

1) Menu Item for Custom Post Type archive

I don’t have an automated solution here. But in my opionion it should be possible to create a similar widget inside the Menu Admin Page to display all Posttypes with an archive and generate a link to it which you than can drag&drop to your desired menu.

2) Post Template for Custom Taxonomy

If you display a term of a custom taxonomy, the default archive.php template is used. You could use some conditional statements to display content based on the taxonomy or the post type e.g. if(is_tax('YOUR_TAX') || is_post_type_archive('YOUR_POSTTYPE')). It should also be possible to use archive-{tax}.php for a static template file, but haven’t tested it with the post type archives.

3) Permalink for Custom Taxonomy

During registration, you could set the rewrite parameter. So you could basically generate something like this:

http://yourblog.tld/parent/cpt/<post>    
http://yourblog.tld/parent/cpt/taxonomy/<post>

To do this, you have to register your custom post type first with a special rewrite parameter. Than you register a new taxonomy object with register_taxonomy_for_object_type for your custom post type before you register your custom taxonomy. As described by Jan Fabry in a answer here on SE, this is necessary for the correct order of the generated rewrite rules.

Custom Post Type

$args = array(
    // your arguments
    'rewrite' => array('slug' => 'parent/cpt', 'with_front' => false)
);

register_post_type('YOUR_POSTTYPE', $args);
register_taxonomy_for_object_type('YOUR_TAXONOMY', 'YOUR_POSTTYPE');

Custom Taxonomy

$args = array(
   // your arguments
   'rewrite' => array('slug' => 'parent/cpt/taxonomy', 'with_front' => false)
)

register_taxonomy('YOUR_TAXONOMY', array(), $args);