For what it's worth, I have never thought that Fortunate Cloud and Quasar were the same ship. But I have never thought it surprising that Jonas and Hethor know each other. Ships dock at the same ports, sailors frequent the same taverns, and, too, they jump ship and sign onto others. OTOH, I've only just begun to seriously entertain the thought that Hethor may indeed be KLS---a name, I have argued for 2 years, Chris, undoubtedly Korean.
FC and Q are (or were) a different order of ship than Tzadkiel's, more mundane, I would say, but also subject to the timewarps of space. (Or do I mean the spacewarps of time?) Thus, though Tzadkiel's ship really is the only one of its kind, there are or were others of a different kind. Hey, there's the Whorl!
-alga-