I have not been able to completely repair the AF117a disk's filesystem errors using DiskSalv or FixDisk. I wouldn't normally use FixDisk to attempt this as it doesn't keep track of loose blocks (files without a header), but I'm sure there are none on this disk (it's almost 100% full as far as I can tell).
Using DiskSalv to validate and then repair the disk results in the Fiasco 2.2 lzx archive being destroyed, because the ProText data file has overwritten some of its allocated blocks and DiskSalv 'repairs' the cross-linked files by destroying the original, partly-overwritten one and preserving the more recent, but nonetheless unwanted and almost certainly incomplete one!
On the other hand, FixDisk does have a feature to enable files to be wiped before attempting to 'undelete' the remainder. However, using it to validate the disk and then wipe the ProText data file results in no recoverable data found!
I now think the only way I'm going to completely recover this filesystem is by taking a copy of the DiskSalv validated disk image and using a binary file editor to repair the corrupted data blocks by overwriting them directly with good data copied from the two lzx archives I have reconstructed and then attempting a DiskSalv repair on the resulting image.
It is a FFS disk, so the data blocks don't have the file headers required by the standard file system.