Now pending posts get displayed to anyone and private posts are still only visible to admins

saves-drafts-posts.php

/*
 * How to make draft posts or posts in review accessible via full url / slug.
 * Source: - https://wordpress.stackexchange.com/questions/218168/how-to-make-draft-posts-or-posts-in-review-accessible-via-full-url-slug
 */
	function auto_save_post_status( $post_id, $post, $update ) {

		if( $post->post_status == "draft" && ! $post->post_name ) {

	        remove_action( 'save_post', 'auto_save_post_status', 20, 3 );

	        wp_update_post( array( 'ID' => $post_id, 'post_status' => 'publish' ) );

	        wp_update_post( array( 'ID' => $post_id, 'post_status' => 'draft' ) );

	        add_action( 'save_post', 'auto_set_post_status', 20, 3 );
	    }

	}
	add_action('save_post', 'auto_save_post_status', 20, 3);