Don't think it really needs to apart from note messages (keys) and knob cc's which I think get sent to organelle in any patch. This patch sounds dope - did you find the source of that delay effect on voice one of the harmonizer @shreeswifty? Do you think it would be possible to map the voices in the same way they are in C&G's Granular Freezer Patch too?
When we last spoke you said you hadn't tried the patch out yet.
The way the keys work is that middle C is unity, all other keys are pitched chromatically from there (low c is an octave down etc.).
There is Dry/Wet Control which could stay for your patch. (This could be very cool to sweep in and out while holding a chord)
There is a latched and unlatched mode enabled with the Aux Button. Your patch could have 4 voice polyphony, but have the option of using just one, two or three voices depending on how many keys in a chord are being pressed. Let me know how much work this requires, I might be asking the world. (Gonna increase my donation later tonight I hope)
This was my sorta thinking for how the keys could work in a vocal harmonizer patch. For desired tunings and chords outside this range, perhaps an external midi keyboard or midi sequencer would do the work. This seems to be the kind of setup Jacob Collier uses (midi keyboard).