Yep, it was part of my claim that the two Scylla's are either the same or relatives (a younger sister or child, perhaps -> there is the scene in Return to the Whorl where Hoof looks at a smaller bride on the sea and asks if that is Scylla, and Silk seems to skirt the question. Note that he doesn't have to communicate with the Scylla of Blue after he returns to get Seawrack. And she IS a spy, (100% guarantee :)))
As far as church music goes, of course Bach was the master, but there are some cool contemporary ones like "I am the Bread of Life" which is directly cribbed from the gospel of John (and the refrain "I will raise you up on the last day" strikes a nice eschatological "Terminus Est" kind of resonance)
Marc Aramini