Just to follow up on this, I spoke with the tech(s) and they said an arduino+relay should work fine to close the contacts on the loop start/stop footswitch based on MIDI signals, but they also pointed out that the 1440 looper pedal has MIDI control as one of its key features, and it’s very reasonably priced, so I just ordered one of those instead of risking my new Grand Canyon with a homebrew solution.