Retain "Last edited by" info
You can do that by implementing hook_node_presave in your custom module, by something like:

function MODULE_node_presave($node) {
  $recent_copy = array_shift(array_values((node_revision_list($node))));
  drupal_set_message('User id of the user who edited latest is '.var_export($recent_copy-&gt;uid, TRUE));
  drupal_set_message('Username of the user who edited latest is '.var_export($recent_copy-&gt;name, TRUE));
}


You can find a detailed solution see: Get the edited node details without enabling node revision in Drupal.