REST API Error while creating Purchase Requisition

Summary:

I am trying to create a Purchase Requisition using the Oracle Fusion REST API:

POST - /fscmRestApi/resources/11.13.18.05/purchaseRequisitions

It seems the API is unable to uniquely identify the Supplier Contact because multiple records exist with the same name (Cote, Kelly).

Question-

1. How should SupplierContact be passed in the REST API when multiple contacts exist with the same name?

2. Should we pass an internal ID instead of name?

3. Is there a way to uniquely identify the Supplier Contact using:

Contact ID
Person ID
Email

4. Is there any API to fetch the correct Supplier Contact identifier to use in the requisition payload?