I contacted Maria Elena Gammon, senior product manager for SIPM. Noted below are the answers that she provided to your questions:
1) The Export Organizations web service is an inbound service that enables you to export information about the organizations configured for your site. This web service receives OrganizationExportWSRequest messages and responds with OrganizationExportWSReply messages. The organization Export Webservice Reply message exports a 64base encoded zip file. This is a CSV file has an element called systemid. This is the buyersystemid.
2) See answer above for question 1
3) Systemid is included in the CSV files.
4) Yes, the organization export and supplier profile export Webservices sends the data in CSV files. Same data elements you see in Data Dictionary file ExportOrganizationtoCSV.
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