Ordering Posts Type A by Custom Fields of related Post Type B

This works. The filters are tied to a custom 'orderby' term and removed after the query.

$args = array(
    'post_type'         => 'artworks',
    'posts_per_page'    => -1,
    'no_found_rows'     => true,
    'order'             => 'ASC',
    'orderby'           => 'artist_name_artwork_title',
);

add_filter('posts_join', 'name_join', 10, 2 );
add_filter('posts_orderby', 'orderby_artist_name_artwork_title', 10, 2);

// query
$wp_query = new WP_Query( $args );
remove_filter('posts_join', 'name_join', 10 );
remove_filter('posts_orderby', 'orderby_artist_name_artwork_title', 10 );

function name_join($joins, $wp_query) {
    if ( $wp_query->get( 'orderby' ) != 'artist_name_artwork_title' ) {
        return $joins;
    }   
    global $wpdb;        
    $joins .= "  LEFT JOIN $wpdb->postmeta name ON name.post_id=$wpdb->posts.ID AND name.meta_key='artists_name'" ;
    $joins .= "  LEFT JOIN $wpdb->postmeta lastname ON lastname.post_id=name.meta_value AND lastname.meta_key='artist_last_name'";
    $joins .= "  LEFT JOIN $wpdb->postmeta firstname ON firstname.post_id=name.meta_value AND firstname.meta_key='artist_first_name'";
    return $joins;
}

function orderby_artist_name_artwork_title($orderby_statement, $wp_query) {
    if ( $wp_query->get( 'orderby' ) != 'artist_name_artwork_title' ) {
        return $orderby_statement;
    }   
    global $wpdb;
    $orderby_statement = "lastname.meta_value, firstname.meta_value, $wpdb->posts.post_title";
    return $orderby_statement;
}