A suggestion.  If we've got a Warden character (which is sounds like Archivist is going to be playing), then he would definitely know a lot of the players.  According to the books, Wardens are assigned territory - for example, when Harry becomes a Warden, his territory is Chicago.  So, if Archivist plays a Warden, he'd know a good number - especially any other Wizards, Sorcerers, and Focused Practitioners, since they all deal with the same magic as the Wardens.