Switching attention away from display and ideas of controls we can get some progress in acquiring parts.
First off, an unescapable requirement is MIDI output sockets. MIDI uses 5-pin 180ยบ DIN sockets, like these.
Secondly, during initial development at least I figured to use a breadboard.
Along with a breadboard I would need to “wire it up”, and for breadboard purposes a nice little jumper wire kit would be very handy.
These “essentials” were all purchased, joining the Arduino in the starts of a pile of parts and components on my desk… at work…
B.