a) Windows Explorer would be able to use the deltas to reconstruct files?
No. In the non-native ways, each incremental contains only complete files. Not partial files.
To back up big files partially with versioning, there is only one way, and it's called "Synthetic Backup". It combines the native method described above with Partial File Updating. I.e. Zipping, Versioning, Filename Encoding, and Partial File Updating. It is on the tab sheet Versioning->Synthetic Backup in version 5. See also
http://www.superflexible.com/history.htm.
b) I've never used a program that fully automated backup files' creation, storage, and retrieval for restores. Is it recommended to let SFFS handle/automate backups and restores using its native abilities (so that "traditional" (manual) management/administration of backup files would be a thing of the past)?
Yes, definitely. But some users want to use it differently, so that is fine, but less automated, and can't use partial backups for large files.
c)Would there be any benefit to "traditional" (manual) backup file management/administration if I was willing to use that technique?
I don't see what's manual there - except for the restores? The benefits are mainly the preferences of the customer. Some feel better with few big ZIP files rather than lots of small ones, for example. Big ZIP files might transfer faster over the Internet.