How can the recipients and content for comment email notifications on a custom post type be changed?

I did it the long way, with help from a related WordPress.org support thread:

add_action('comment_post', 'notify_author_of_reply', 10, 2);

function notify_author_of_reply($comment_id, $approved){

  $comment = get_comment($comment_id);
  $post_id = $comment->comment_post_ID;
  $post = get_post($post_id);

  if($approved && (get_post_type( $post_id )=='ticket')) {

    $supervisor = get_userdata( get_post_meta($post->ID, 'assigned_by', true) );
    $operator = get_userdata( get_post_meta($post->ID, 'assigned_to', true) );
    $client = get_userdata( $post->post_author );

    $recipients = array(
      $client->user_email,
      $supervisor->user_email,
      $operator->user_email
    );

    $current_user = wp_get_current_user();

    if (($key = array_search($current_user->user_email, $recipients)) !== false) {
      unset($recipients[$key]);
    }
    wp_mail($recipients, 'New comment', 'Dude you got a reply...');
  }
}