Get order of a content type's fields
Use field_info_instance()
  $entity_type = 'node';
  $field_name = 'body';
  $bundle_name = 'article';
  $body = field_info_instance($entity_type, $field_name, $bundle_name);

Which gives you access to numerous config/settings

  $body_weight = $body['display']['default']['weight'];