Looking to be a good start 
Swillkb is known to generate plates with approximative precision, less and less people are using it nowadays.
You can generate a better plates with AI03 plate generator: https://kbplate.ai03.com/
As to how to manufacture the plate, you can use one of the laser cutting services available, there is a thread here that gives different links: List of laser cutting services
With the number of switches that you have, I’d recomment the venerable Teensy++ 2.0.
This is also an Atmega MCU, writing your first QMK firmware on it will be easier than on ARM MCUs.
QMK have support for MIDI so adding this feature should not be very complicated, but I never tested this feature.
Can’ t wait to see your progress 