4. (to eXch): Is there any special treatment in place if it comes to your attention that fraudulently gained crypto goes through eXch?
They find out about it only after the exchange is complete, like the one in the @matrixconnor case. Unfortunately, by then it is already too late to do anything. Everyone should take care of their money, they should not expect that someone else will do it for them.
I think it is impossible to check if the fund comes from a fraudulent activity or not before sending... the service would be very slow. And honest users could have been freeze by mistake.