Only an emergency potty on the Mustang - and it gets pretty cozy with more than 2 pax. Although Wijet is in the process of replacing their Mustangs with Hondajets (with lavs and wifi), lets see how that will turn out..
I think Jetclass is pretty much just taking what's available and cheap on the market - it seems like Surfair will have long term contracts (maybe even fully assigned aircraft?) with mentioned operators.
I don't think they will use the PC12 in the near future. It just got EASA certified last year and there are not many (any?) operators in Europe yet. Buying doesn't seem to be the long term strategy either since they just surrendered their Part 135 in the US.