Complicated Permalink Structure

I have read alot of articles and done quiet a bit of filtering. I can accomplish parts of my requirement with any given filter or plugin, but when I combine them, I do not succeed. I need to:

1. Remove Parent level category from slug. This works fine, and also works with CPTs with a modification.

   add_filter ( 'post_link', 'remove_parent_cats_from_link', 10, 3 );
   function remove_parent_cats_from_link( $permalink, $post, $leavename ) {
   
   	$cats = get_the_category ( $post->ID );
   	if ( $cats ) {
   		usort ( $cats, '_usort_terms_by_ID' ); // order by ID
   		$category = $cats[ 0 ]->slug;
   		if ( $parent = $cats[ 0 ]->parent ) {
   			$parentcats = get_category_parents ( $parent, false, '/', true );
   			$permalink  = str_replace ( $parentcats, '', $permalink );
   		}
   	}
   
   	return $permalink;
   }

2. Add /%category%/ with removed parent to 3 custom post types. I added Custom Post Type Permalinks plugin and it works great with the /%category%/ for each CPT. It even picks up the filter to remove the parents with this
   `add_filter ( ‘post_type_link’, ‘remove_parent_cats_from_cpt’, 10, 3 );
   function remove_parent_cats_from_cpt( $permalink, $post, $leavename ) {

   if ( ( ‘hmk_recipe’ == get_post_type ( $post ) ) || ( ‘hmk_craft’ == get_post_type ( $post ) ) || ( ‘hmk_article’ == get_post_type ( $post ) ) ) {

   $cats = get_the_category ( $post->ID );
   if ( $cats ) {
   usort ( $cats, ‘_usort_terms_by_ID’ ); // order by ID
   $category = $cats[ 0 ]->slug;
   if ( $parent = $cats[ 0 ]->parent ) {
   $parentcats = get_category_parents ( $parent, false, ‘/’, true );
   $permalink = str_replace ( $parentcats, ”, $permalink );
   }
   }

   }

   return $permalink;
   }`

3. Remove the /custom-post-type/ base from those 3 types of posts too. When I filter to remove that from the url, I get 400 errors. Here’s the code.

   function hmk_remove_cpt_slug_craft( $post_link, $post, $leavename ) {
   	if (  'hmk_craft'  != $post->post_type   ||  'publish' != $post->post_status ) {
   		return $post_link;
   	}
   
   	$post_link = str_replace( '/' . $post->post_type . '/', '/', $post_link );
   //	$post_link = str_replace( '/' . $post->post_type . '/', '/%category%/', $post_link );
   
   	return $post_link;
   }
   
   add_filter( 'post_type_link', 'hmk_remove_cpt_slug_craft', 10, 3 );
   
   function hmk_parse_request( $query ) {
   
   	if ( ! $query->is_main_query() || 2 != count( $query->query ) || ! isset( $query->query['page'] ) ) {
   		return;
   	}
   
   	if ( ! empty( $query->query['name'] ) ) {
   		$query->set( 'post_type', array( 'post', 'hmk_article', 'hmk_craft', 'page' ) );
   	}
   }
   add_action( 'pre_get_posts', 'hmk_parse_request' );

I feel like I’m doing too much filtering on these permalinks, and because I have used the plugin to add the /%category%/, I wonder if that’s not causing a conflict with my filters.

Also for the CPTs I have tried turning off the plugin and just adding /%category%/ to my filters. You may see that commented out. No luck.

Also I tried adding /%category%/ in the $rewrite options when I create the CPTs. Still no luck.

I am pretty green with this Rewrite API, so your help or advice is greatly appreciated.