I think I'd prefer to work with Craftworld Eldar, the Harlequins tend to be mercurial at best and we might be able to help with their population issues. Also, the Harlequin idea of diplomacy is to show up, kill a bunch of people, and then explain why they are there, so I'm not sure we want to invite them anywhere near us or people we are friendly towards.In terms of intrigue focused characters, we could try recruiting a Harlequin troop. We may be able to create a device that shields them even more from Slaneesh than Cegorach can manage, allowing them to use more of their true power.