I did not see a free chair for the Little girl among the darkfriends. So I don't think she is a high ranking darkfriens of some sort.

I think she could be ransom that Fares Fares is using to get a darkfriend to do something against their will.

Another theory I have, a bit out there, is that it could be a certain forsaken masked through the Power. Fares Fares might be introducing the Little girl to later reveal she's a Chosen, to warn the darkfriends that now everything they do will be watched, and they can't escape the Chosens' eyes.