I just wanted to get back and answer your original question, which is about using the A4’s sounds, played back by a MIDI file: it’s super easy on the A4 - create a 4 bar pattern, you have to put a trig on an unused channel for example FX track, then copy empty 4 bar pattern X times (as long as your MIDI files are)
Then go in CHAIN MODE and make a chain of all those patterns. You will want to have one empty pattern in the front and have also 4 bars space in your DAW before the first notes hit.
Then just record that stuff into your A4. Yes, it record MIDI files, just like it records notes played by a keyboard.
Cheers. No need to sacrifice the Octatrack’s MIDI sequencer for sequencing your A4, do it straight from the A4.