I didn’t notice any significant latency issues with RPi when translating MIDI CC’s from FF LV1 to OT. Controlling volume levels, crossfader, various track parameters etc. but no big delays. Obviously there must be some latency but nothing I could even ‘feel’. Just for the record, with the soft synths on regular PC I can ‘feel’ the latency above 10-13ms. My guess is that if you avoid any audio processing you’ll be fine.