You are doing some good job there. I there is one point you are missing though. That Nema is a specification of size and has little or no relations to the capacity of the motor.
In my case, my CNC is controlled by the Pi. I have Dual H bridge motor controllers for each axis.
Nema is a specification of size and has little to no bearing on the motor's torque or capacity.
I'm using a Pi to control my CNC.I also have Dual HBrige motor controllers for the axis that I have connected to stepper motors. Finally, I secure a shell in my Pi and launch a script to analyze the G codes and manage the motors. Except for Pi, H Briges and motors, I have got everything I require at home depot.
Never let any mechanical device know that you are in a hurry.