My apologies, I didn’t realize I missed the mark on what was needed!
The ID field for each table is unique in that they are fully system-generated/maintained and not currently available in schema config. I found a feature request on GitHub ( #4288 ) to allow unhiding ID fields in the schema for this same purpose of reducing unintended duplication when importing via WorkBench. I left a comment relaying that you both also request that this feature be implemented in a future release.
Let me know if you have further questions or if there are more details or context you’d like the development team to be aware of and I’ll add it to GitHub 
Best,
Bronwyn