As it would turn out, I have one of these cards as well. I have quickly made-up a VGA pass-through cable and a Feature Connector, in use with my Video 7 VRAM II card on a 486 PC. I have managed to make the card work - precisely once (and "work" loosely - the display was a bit corrupted) - in DOS using the "Video II" driver/software.
For the Feature Connector, it's just a 26-pin ribbon cable, but the Feature Connector is fiddly at best. I chose the VRAM II card because it was similar enough in age (1991) to likely be compatible. I made a pin-to-card-edge cable with some IDC crimps.
For the VGA passthrough, the card needs a dongle (loops back to VGA card output, goes into the card with tee-off for one or more RCA jacks as "inputs"). I simply used a VGA cable and broke-off pins 4 and 5, as they were grounding the RCA composite video signal (they re-used grounds as signals). VGA cables are a dime a dozen; cards like this are not. Then, the composite jack on the card (supposed to be "output"/passthru) serves as an input.
I'd absolutely love to help figure out that hard drive dump if you have any issues, and replicate the software setup on my PC and card! If you have any trouble, maybe we can meet up on Discord etc.
Hopefully we can get a working "software bundle" put together from what's on your drive, and get it over to The Retro Web to archive it!