TWC Enterprises was formed when Tri White and ClubLink consolidated and reorganized a bit. Can't remember the exact details, or manage to find them at the moment. Just another corporate shell.
As for "Mediterranean Cruise Holdings", this very well might be some new corporate entity created specifically to hold the WP&YR, which is why it may not show up yet. Could very well be a partnership amongst cruise lines, hence the new entity.
Regardless, cruise line ownership of the WP&YR would bode well for survival, but in a prepackaged, shrinkwrapped and mass-marketed sort of way. Not so much for charters, I would fear, as getting a giant corporate monolith to understand and work with railfans can be rather challenging.
Still all just speculation, but YukonYeti (the guy who posted this on TO) usually isn't full of it.