Woocomerce Back in Stock Product Help

// Add the extra option 'Back in Stock' to the dropdown on the product edit page
function filter_woocommerce_product_stock_status_options( $status ) {
    $status['back_in_stock'] = __( 'Back in Stock!', 'woocommerce' );
    return $status;
}
add_filter( 'woocommerce_product_stock_status_options', 'filter_woocommerce_product_stock_status_options', 10, 1 );

// The text to display on the front-end (if needed)
function filter_woocommerce_get_availability_text( $availability, $product ) {
    switch( $product->get_stock_status() ) {
        case 'back_in_stock':
            $availability = __( 'Back in Stock!', 'woocommerce' );
        break;
    }
    return $availability;
}
add_filter( 'woocommerce_get_availability_text', 'filter_woocommerce_get_availability_text', 10, 2 );

// Add a class to <li> for use in css styling (if needed)
function filter_woocommerce_get_availability_class( $class, $product ) {
    switch( $product->get_stock_status() ) {
        case 'back_in_stock':
            $class = 'back-in-stock';
        break;
    }
    return $class;
}
add_filter( 'woocommerce_get_availability_class', 'filter_woocommerce_get_availability_class', 10, 2 );

// Display the custom status in the back-end product list
function filter_woocommerce_admin_stock_html( $stock_html, $product ) {
    switch( $product->get_stock_status() ) {
        case 'back_in_stock':
            $stock_html = '<mark class="pre-order" style="background:transparent none;color:#33ccff;font-weight:700;line-height:1;">' . __( 'Back in Stock', 'woocommerce' ) . '</mark>';
        break;
    }   
    return $stock_html;
}
add_filter( 'woocommerce_admin_stock_html', 'filter_woocommerce_admin_stock_html', 10, 2 );

// The code to add a custom attribute to woocommerce products shortcode
function htdat_shortcode_atts_products( $out, $pairs, $atts, $shortcode ){
  if ( isset ($atts[ 'backinstock' ]) && $atts [ 'backinstock' ] ) {
    $out[ 'backinstock' ] = true;
  } else {
    $out[ 'backinstock' ] = false;     
  }
  return $out;
}
add_filter('shortcode_atts_products', 'htdat_shortcode_atts_products', 10, 4);

// And then what the shortcode attribute 'backinstock' actually does
function handle_custom_query_var( $query, $attributes  ) {
    if ( $attributes[ 'backinstock' ] ) {
        $query['meta_query'][] = array(
            'key' => '_stock_status',
            'value' => 'back_in_stock',
            'compare' => 'IN',
        );
    }
    return $query;
}
add_filter( 'woocommerce_shortcode_products_query', 'handle_custom_query_var', 10, 2 );

'orderby' => 'date', //that's the date it was first published, woocommerce products shortcode does not by default include ordering by date modified, unfortunately
'order' => 'DESC',
'limit' => 300, // (the number of products you want to show in total, but if you also use the next 'pagination' argument, then it is the number of products per page)
'pagination' => true

// Sort Products by modified date when using WooCommerce's products shortcode
function backinstock_pre_get_posts( $query ) {
    // do not modify queries in the admin
    if ( is_admin() ) {
        return $query;
    }
    // only modify queries on the page where you have your shortcode [products backinstock=true]
    if( is_page('products-back-in-stock')) {
        $query->set('orderby', 'modified');
        $query->set('order', 'DESC');
    }
    return $query;
}
add_action('pre_get_posts', 'backinstock_pre_get_posts');

            'key' => '_stock_status',
            'value' => 'back_in_stock',
            'compare' => 'IN',
            'orderby'  => '',
            'order'    => '',