IOS – Extract iCloud Password from iTunes backup

It depends whether the remaining files you have are from an encrypted backup.

It won't be feasible to read your backup data if you have an encrypted backup with no Info.plist, Status.plist, or Manifest.mbdx files

However, if your backup wasn't encrypted, it will be possible to read that data. You'll find that whilst the filenames are unhelpful (they're SHA-1 hashes of the file's internal path), the file contents easily readable. It's only the filenames that'll be lost.

If you're looking for images, try renaming a bunch of the files to have .JPG extensions, and see whether Windows Explorer or macOS Finder previews them for you.

There are a few approaches for digging into what's there in bulk. You mentioned using iPhone Backup Extractor, and there's a guide on how a use "Bulk Rename Utility" to read backup data when in this situation.

I had the same problem. Fixed it by turning off all sharing (the checkbox options on the right of the panel), THEN trying to delete again.