@Leonie Fedel Hi Leonie.
Did anyone get back to you on your question?
I was a developer at PSft and worked on the Supplier Comprehensive Portal etc. but I don't currently have access to a PeopleSoft system with Supplier Change Requests, so I'm working from memory and it's been a few years.
Is it possible the issue for internal staff not seeing Government Classification fields is related to Security setup?
For your 2nd question about allowing Supplier to upload documents during the change request wizard - have you checked PSoft documentation to see whether this is allowed or not?