I don’t see that being quite that useful considering you’ll be punching in your next sequences and possibly a new project while you are soloing one track. The Octatrack IS a MIDI controller, and a good one, for the other boxes.

Just watch the vids of all the “masters” with 4 Elektrons- not a keyboard in sight and the only MIDI controller I saw was a DIY thing that emulated the “joystick” modulation thing from the Monomachine keyboard edition.

But to each his own: if that’s the way you see it all working for you then go for it!