I am curious how the words "polyphonic pitch shifting" are being interpreted by both the OP and Eventide. 

Well, there are different techniques one can use for pitch shifting;  this short wikipedia page gives a general overview of the different techniques:

https://en.wikipedia.org/wiki/Audio_time-scale/pitch_modification

We assumed given the example of the Pitch Fork, that what was being requested was a frequency domain, phase vocoder style pitch shifter with some improvements.