Yeah, I plan that Vholdran finds 'something' what interests Methu in Malcanthet's vault. So give artifact requests or perhaps means steal one radiant sisters (which only Methu can do one reason or another). Vholdran drops intel/info on table and then it's rather quick process how mission is then performed. As if you barge in right now, it can lead very messy operation or even fail. The alliances or any add chances to succesfully do operation but aren't mandatory.