Hi, I have been reading the project and it is interesting.
Your idea of sending a MIDI serial note and generating a tone in parallel seems plausible.
You can use any arduno board because does not look like a very complicated code.
It would be basically a mix of the program uploaded by evankale (github.com/evankale/ArduinoMidiDrums/blo...ArduinoMidiDrums.ino
) and the sinewave generator program.
At the time that the evakale code generates the midinote ("noteFire" in the code), you can try to generate a sinewave for some hundreds of milliseconds.
So, for me seems plausible, but first of all, you need to understand how evankale code works, how the pedalshield tone generator (sinewave generator) code works and try to mix both together.