In a multi-system landscape, maintaining data synchronization requires a robust Identity Mapping strategy.
The standard Salesforce architectural recommendation is to use External ID fields to store the unique identifiers from each secondary system.
By storing the ERP ID, Ticketing ID, and Data Lake ID as External IDs in Salesforce, the middleware can perform upsert operations without needing to first query Salesforce for its internal ID. This reduces the number of API calls and simplifies the integration logic. Conversely, when Salesforce pushes a change to the ERP, it sends the stored ERP ID, allowing the ERP to instantly identify the correct target record.
Option B (Caching at the middleware) is a high-maintenance "anti-pattern" that introduces a new point of failure if the cache goes out of sync with the actual systems. Option C (Change Data Capture) is a mechanism for notifying systems of changes, but it does not solve the underlying identity mapping problem. Using External IDs creates a stable, searchable, and performant cross-reference that is the backbone of any successful "hub-and-spoke" integration architecture.