Correct. The difference would be that Pirate's scam has innocent victims while the PPT operator's scam has only one victim -- Pirate.
Not true. There's a good chance pirateat40 still has funds which could be recovered in order to partially refund investors - this has happened before in other ponzis - but if the PPT investors' funds were never invested in Pirate then there's nothing to recover.
If there were a Pirate recovery, the PPT operators would have to pay that recovery to their customers, whether they got the funds from Pirate or not.
Surely that wouldn't be a "completely separate scam" if people agreed to it? And there's no rational reason a person who invested in a PPT wouldn't be equally happy in a "synthetic PPT". You have to trust the PPT operator to pay you in either case.
If Pirate did actually pay out in full, how exactly would this hypothetical "synthetic PPT" be able to pay their investors though? They wouldn't, which means they had no intention to pay their investors regardless of whether Pirate fails, which means they themselves were operating a ponzi and scamming their investors.
They would pay their investors out of their own funds. I'm not sure how you know they wouldn't. This actually would have been a really, *really* good bet. And you could cut your losses at any time by passing funds to Pirate. It's actually a very sensible business model.