The information you're looking for is available on microfilm from the National Archives. Also, as for the ones who died there, I have a book title CONFEDERATES WHO DIED IN NORTHERN PRISONS AND WERE BURIED IN NATIONAL CEMETERIES. Most of the men and women who died at GSMP are buried here in St. Louis at Jefferson Barracks National Cemetery. If there's a particular person you're looking for, email me at firstname.lastname@example.org
and I'll see if he/she is in the book.