In a complex landscape where multiple systems contain overlapping customer data, each with its own primary key, the core architectural challenge is Identity Management. To ensure that an update in Salesforce (the System of Record) correctly updates "Customer A" in the ERP and "Customer A" in the Data Lake, a Master Data Management (MDM) strategy is required.

An MDM solution creates a Cross-Reference (X-Ref) Table or a "Golden Record" that maps the unique identifiers from all systems. In the Salesforce record, the architect should implement External ID fields for each corresponding system (e.g., ERP_ID__c, Ticket_System_ID__c).

Why this is the superior recommendation:

Bidirectional Integrity: When the middleware receives an update from the ERP, it uses the ERP_ID__c to perform an "upsert" in Salesforce, ensuring no duplicates are created.

Traceability: It allows for easy auditing of data lineage across the enterprise.

Decoupling: Salesforce doesn't need to know the internal logic of the ERP; it simply holds the reference key.

Option B (CDC) is a delivery mechanism, not an identity management strategy; it tells you that something changed, but not which record in the ERP it corresponds to without the ID mapping. Option C (Local caching in middleware) is an "anti-pattern" because it makes the middleware stateful; if the middleware cache is lost or out of sync, the entire integration breaks. By designing an MDM-based mapping solution directly within the data model, the architect ensures a robust, scalable, and transparent identity framework for the entire enterprise.