toastiestudio

A fix for the plugin code that would still allow exclude_from_search to be true would be:

line 495 duplicate-post-admin.php
replace
//$children = get_posts(array( 'post_type' => 'any', 'numberposts' => -1, 'post_status' => 'any', 'post_parent' => $post->ID ));
with

$duplicate_post_types_enabled = get_option('duplicate_post_types_enabled', array ('post', 'page'));
	if(!is_array($duplicate_post_types_enabled)) $duplicate_post_types_enabled = array($duplicate_post_types_enabled);	
	$childargs = array('numberposts' => -1, 'post_status' => 'any', 'post_parent' => $post->ID, 'post_type' => $duplicate_post_types_enabled);
	
	$children = get_posts($childargs);

I wrote the code myself.

This is the post type

function create_resources_post_type() {
	register_post_type( 'dcr-resources',
		array(
			'labels' => array(
				'name' => _x( 'Resources', 'my_custom_post','custom' ),
        		'singular_name' => _x( 'Resource', 'my_custom_post', 'custom' ),
     	  		'add_new' => _x( 'Add New', 'my_custom_post', 'custom' ),
      			'add_new_item' => _x( 'Add New Resources Post', 'my_custom_post', 'custom' ),
        		'edit_item' => _x( 'Edit Resources Post', 'my_custom_post', 'custom' ),
        		'new_item' => _x( 'New Resources Post', 'my_custom_post', 'custom' ),
        		'view_item' => _x( 'View Resources Post', 'my_custom_post', 'custom' ),
        		'search_items' => _x( 'Search Resources Posts', 'my_custom_post', 'custom' ),
        		'not_found' => _x( 'No Resources Posts found', 'my_custom_post', 'custom' ),
        		'not_found_in_trash' => _x( 'No Resources Posts found in Trash', 'my_custom_post', 'custom' ),
        		'parent_item_colon' => _x( 'Parent Resources Post:', 'my_custom_post', 'custom' ),
        		'menu_name' => _x( 'Resources', 'my_custom_post', 'custom' ),
			),
			'description' => 'Resources Posts',
        	'supports' => array( 'title', 'editor', 'excerpt', 'thumbnail', 'revisions', 'custom-fields', 'page-attributes'),
			'taxonomies' => array('dcr-resources_categories'),
			'hierarchical' => false,
 			'public' => true,
			'show_ui' => true,
			'show_in_menu' => true,
			'menu_position' => 25,
			'menu_icon' => 'dashicons-carrot',
			'can_export' => true,
			'has_archive' => true,		
			'exclude_from_search' => true,
			'capability_type' => 'page',
			'rewrite' => array('slug' => 'resources','with_front' => FALSE),
		)
	);
}
add_action( 'init', 'create_resources_post_type' );