don't know if it helps
I'm going down the same route! (<- you see what i did there!)
I have written a gcode interpreter for exactly that setup, 3 EasyDrivers connected to a Uno
I have also written a piece of software that sits on the PC and feeds gcode to it
Stir in Eagle and pcbgcode and I have a complete "design" to "cut" solution
If you like I can post the software