Multiple controllers in Live
The performance software for Automaton has been chosen, and it will indeed be Ableton Live! Today I confirmed that Live allows two controllers to be used to control the same set of clips.
To test this I configured both Launchpad Mini and Maschine Studio as controllers in Live. The former is very simple to set up, coming with a factory installed template; the latter is a little more involved, though still easy if you follow Native Instrument's instructions.
With both controllers set up I was able to trigger the same clips from both. Also, because the Launchpad Mini was being used in the DAW it was designed for, its pads lit up correctly. Even more usefully, each controller updated its clip state when the other was being used. One question for me now: how do I notate Ableton clip triggering in the score?
I finished off today by comping the final vocal part and importing all the comped vocals into Automaton's main Logic session (check those tasty purple regions at the bottom out).