As for what is Calypso, I think that was just a nickname of one of the developers.
This all came from some forgotten backups.

As for the last question I'll make it short. There wasn't any work done on that, but everything would depend of course how Epic were going through with the PS2 UT and what not.
Of course later that was already released so I suppose it would be trivial to just port the finished Jazz 3 stuff on PS2, or perhaps even the engine of the PC release would have been upped to match the engine version of the PS2 engine...