All that's known so far is that Anya and Elisabeth were the former agent partners of Montgomery Osbert, back when Assassins worked in three-person teams, and they aren't currently involved in PPC affairs, since Osbert is the "oldest Agent currently active", though he's been part of Personnel ever since he got too old to actively go on missions. It's not known if they died, or retired, or went crazy, or what, but Osbert's the only one left, and he never mentions his partners.
There's good story potential behind that, actually. The first members of the Department of Mary Sues, back before the need for Departments existed, and it was just the Poppy taking a chance on three human interlopers. There's still a lot of ground to explore there.
There are also a few ideas I had about the Origin Civil Wars that this story stirred up, since there's still a lot of space for what the main government of Origin was doing, what happened on Origin after most of the Firstborn left to form the Organisation, and the like, which I think could also make a good story.
I think what I liked most about Origins was that, while it does make a good story in itself, it also creates numerous spaces that other stories could fit into, much like how PPC continuity works as a whole. I don't know if that was intentional, but if it was, it was brilliant.
Wait. I just realized something. If Makes-Things was with the PPC since the early days, even before any other humans, but Osbert has been there since the early 1980s(judging by the rough timelines I've found that may not be exact), how is Makes-Things still so young? I've seen Makes-Things described as appearing to be under thirty before, but the 1980s were themselves thirty years ago. Is there something he created that slows down his aging? Is he secretly a vampire? Has he actually died multiple times, and each time is reborn from a clone that retains the majority of his memories, Dune-style? Or has he perhaps modified his body to become an immortal heedra with Nausicaä-verse technology? I just don't know. There are so many answers to a confusing question.