You're overthinking this. Whack them all into the same folders, and use keywords etc to categorise them.
would it be better to place all these different derivative file types within subfolders with brief descriptions within in each bucket in the derivatives directory?
ie; Derivitives > Der_001 > folder > family photo scans, another folder, ticket stubs, etc.
or I saw in another thread that Peter has a directory of buckets for camera scans, perhaps I should have a directory of scans from my flatbed scanner?