In February, the domain was updated to be on the same server as exch[.]cash
This is clear proof that it is the same owner.
Great analysis. Your reasoning makes a lot of sense though I still don't understand why Namecheap wouldn't just reveal the entire truth now that they aren't their registrar anymore thanks to which their confidentiality agreement(If there was one) is void now.
We can definitively say that the scammer is sweating because of our combined effort and that's a win for us.