How to reorganize the items returned by wp_list_comments()?

You can use the callback argument for a completely customized rendering of your comment/trackback

function wpse168639commentCb( $comment, $args, $depth )
{
    // do whatever you want in here:
    // Dump what you got:
    var_dump( $comment, $args, $depth );
}

wp_list_comments( array(
    # other arguments...
    'callback' => 'wpse168639commentCb',
) );