I thought I understood how the wiring should be between the arduino and the easydriver, but when things didn't work out, I moved a ground connection, unplugged the USB cable from the Arduino, and happened upon an odd result. Here is a crude layout of how it is currently wired.
The odd thing is that this wiring gives power to both the EasyDriver AND the Arduino. Everything seems to run fine, the motor moves as it should, and nothing smells like smoke. I was under the impression that the M+ on the EasyDriver only fed power to the motor, and that the 5v on the Arduino isn't meant to work as a power input. Am I missing something here? Is it safe to leave it wired like this?