I understand the practicality aspect, and you're probably right. The "language" to program Mdrives is their own ("MCode") - here's a manual:
https://novantaims.com/downloads/manuals/MCode.pdf (<-- note PDF).
A commercial cable is probably a couple hundred dollars, but a homespun cable might be $10-$20 - lots of cheap converters available, then you'd have to source and wire up the connector. I'm not trying to convince you to go one way or the other, just throwing out options. Kind a depends on how much enjoyment you get out of tinkering with these.
The two motors that lock under power are what I'd expect from a motor without a program. I'm not sure about the one that clicks. It may be that it's working and making a step or microstep each time the IO goes positive.
GsT