The one thing I'm not quite sure I understand is the KYC part. There are several exchanges that still do not require KYC, even if they aren't allowed to service U.S.-based customers.
They will be well except if they become bigger, bigger and big enough to attract too many U.S.-based customers, and they will be under serious investigations, lawsuits then sanctions like mixers.
Mixers are like exchanges too, they can have criminal money come in or U.S-based customers come in, but only is well until a day something big happens, they will be seized, shutdown. In other words, problems are always there and it's just when those problems will become actual problems.