Well, then remove all of the other data associated with the customer. CustomerID then is then going to be irrelevant anyway. But frankly, all of your points ar

Well, then remove all of the other data associated with the customer. CustomerID then is then going to be irrelevant anyway. But frankly, all of your points are equally invalid. Replications are a copy. Replace values in replications with faux values if that's required. ETL? Absolutely the same. Logs? sed s/UserID/FauxUserID. You're operating a semi-garage business if it's so hard to comply with GDPR. Data does not belong to you anymore, and you've had a few years to make sure you complied.