Hello,
Congrats on the new H90 and sounds like you have a cool setup!
I’m not familiar with the MPC Live 3 (I’m still using my trusty old MPC 1000 and sometimes a dusty old MPC 60!) but for the VocalShiftMIDI harmonies you’ll just need to figure out a way to program your MPC pads to send MIDI notes/chords. Then send the MIDI output from the MPC to the H90 and make sure all of the channels match, and you should hear harmonies when you trigger the MIDI chords. I’m sure you can get some really fun stuff happening once you sequence some chords on the MPC.
Again, not familiar with the MIDI Q Links, but the MIDI programming on H90 is pretty straightforward. You’ll just need to configure the controller to send MIDI CCs and then you can go to a parameter mapping menu on the H90 to map that parameter to whichever CC you like. https://cdn.eventideaudio.com/manuals/h90/1.1.2/content/edit-modes/parameters.html#mapping
Let me know if you make any progress or need further tips.
