Thank you very much, everyone, for your suggestions.
The recovery software that our guy used (locally - way to compound a problem (fail)) recovered file names, which makes me think it's just attempted to recover patches of old MFT and pull back files from that.
The recovery programs that come back with generic filename, while inconvenient to search through, theoretically actually find valid data to piece together, so it's worth a shot, especially as the priority here is photos (they're of a recently-deceased family member, which is the main reason I've not just written this whole debacle of as a learning experience for those involved)
And Matt, while I generally agree, it's conceivable that the software a professional service may have access to would be better at piecing togther whatever it finds than the freebies/cheapies you can grab off the Internet. They would also do some of that post-checking that Jon rightly mentions is so time-consuming.
Anyway, thanks again. I'll take a look at the various suggestions and see if we can have any more luck.