Try as I might (a couple computers & phone), I couldn’t access your links. So, generically …
Any chance of posting those in a screenshot, parameter listing, or key & intervals? I’m having difficulty narrowing it down: single note shifts, key changes, chord inversions, how many interval changes at the same time, etc.
I’m guessing no MIDI (or problem solved). Do you have access to an Aux switch [+ Y-cable if you keep EXP PED control (which of course you would)]. A keyboard sustain pedal in a pinch. Makes a great momentary switch, with a nice feel to it.
At any rate, you can assign the PITCH A,B,C,D parameters directly, with min. / max. limits of travel. Momentary or latching options in H9 software. Not really my preferred method, but it works. Might get a little flaky with 3,4 parameters assigned to the same switch.
You can also assign an AUX switch to switch between the HEEL TOE extremes of any expression pedal mapping. Great way to shift between two sets of harmonies; faking a HotSwitch function. Unfortunately, I believe that will only be a momentary action. You’d have to hold the switch down for the duration of the harmony change. Of course, if you’re shifting among a handful of harmony / key changes, we’ll have to back up & punt. We’ll figure something out.
Without hearing the example(s), I’m unclear on the 3rd voice comment. My first thought was an adjustment on the DELAY GROUP, coupled with short DELAY D. But if they are parallel (static) intervals, maybe another preset in the HarPeggiator / H910 H949 / PitchFuzz (without the fuzz) vein? If there are simultaneous key-constrained harmonies, then scratch that one.
Sometimes it’s the best tactic to stack 3-4 preset variations sequentially, and step through them. Globally limit your pedal to 4 or eight presets, and cycle through them quickly. Cuts down on the brain work. Other times – if you’re fortunate – simple changing the KEY / SCALE with a switch gets you where you need to go.
Anything is possible. The trick is paring it down to a practical implementation.