获取自定义帖子类型的类别

Question

目前我有以下

    <?php
    /*
    Template Name: Landing Page Template
    */

    get_header();

    global $post;
    $slug = $post->post_name;

    $parent = array(
          'hide_empty' => false
        , 'parent' => 0
        , 'orderby' => 'term_id'
        , 'exclude' => array(1, 16)
    );

    $categories = get_terms( 'category', $parent );
?>


<!-- Banner Image -->
<section class="banner short" style="background-image:url('/wp-content/themes/ewc/assets/img/banners/Banner - Indulge.jpg');"></section>


<!-- Content Section -->
<section class="content category">
    <div class="grid-container">
        <div class="grid-x grid-margin-x grid-margin-y">
            <div class="cell text-center">
                <h1><?php the_title(); ?></h1>
            </div>
            <div class="cell large-3">
                <div class="sidebar">
                    <?php @include('partials/sidebar.php'); ?>
                </div>
            </div>
            <div class="cell large-9">
                <div class="main">
                    <div class="grid-x grid-margin-y">

                        <?php foreach ( $categories as $category ) : ?>
                        <?php
                            $children = array(
                                  'hide_empty' => false
                                , 'parent' => $category->term_id
                                , 'orderby' => 'term_id'
                            );

                            $subcategories = get_terms( 'category', $children );
                        ?>

                            <?php foreach ( $subcategories as $subcategory ) : ?>
                                <div class="cell mar-bott">
                                    <h4 data-target="<?php echo str_replace(' ', '-', strtolower($subcategory->name)); ?>"><?php echo $category->name . '<span>' . $subcategory->name . '</span>'; ?></h4>
                                    <div class="tile-group">


                                        <?php 
                                            $args = array (
                                                  'post_type' => $slug
                                                , 'category_name' => $subcategory->slug
                                                , 'posts_per_page' => -1
                                                , 'orderby' => 'title'
                                                , 'order' => 'ASC'
                                            );

                                            $posts = get_posts( $args );
                                        ?>

                                        <?php foreach ( $posts as $post ) : setup_postdata( $post ); ?>

                                            <div class="tile">
                                                <a href="<?php the_permalink(); ?>" style="background-image:url('<?php the_post_thumbnail_url() ?>');" title="<?php the_title(); ?>">
                                                </a>
                                            </div>

                                        <?php endforeach; ?>

                                        <?php wp_reset_postdata(); ?>

                                    </div>
                                </div>

                            <?php endforeach; ?>
                        <?php endforeach; ?>

                    </div>
                </div>
            </div>
        </div>
    </div>
</section>


<?php
    get_footer();
?>

我需要完成的只是从自定义帖子类型获取父类别/子类别。我有一个自定义的沉迷帖子类型，目前无论显示哪种帖子类型，所有类别都在显示。我将如何遍历该特定帖子类型的所有类别？