One way is to follow the instructions from iZotope and use a MIDI bus (Advanced MIDI device).
Another is to route everything in a similar fashion to the workflow Ryan Harlin describes for Neptune in this video:
The only thing left to do is to create a MIDI lane for VocalSynth.
Both ways work fine when I play my keyboard.
However, if I try to introduce Player devices into the equation, I can't get them to "feed" into VocalSynth2.
What am I and my foggy brain missing? Do you have any experience? Thanks in advance for help regarding the setup.