The components for the Inhibit driver arrived yesterday. I populated the module, plugged it in, connected the inhibit lines, and loaded the arduino with a checkerboard memory test I wrote a couple of weeks ago.
No memory errors after 100,000+ iterations, each iteration consisting of writing a pattern byte (0x55 or 0xaa) to all memory locations, then reading all memory locations, checking the data read against the pattern.
This project is now complete, and I can move on with the rest of the ED-64 build. Yay!