Here's where I'm stuck on this question: Is it possible to directly hook up the SoftStep foot controller to tthe PitchFactor, without a SoftStep MIDI Expander?  I suppose that it would involve providing USB power to the foot controller, and using the Expand port to connect to the PitchFactor.  I can't determine if this is a viable (or even safe) option for MIDI routing.

Of course, if you do have a SoftStep MIDI Expander, then I can follow up with a step-by-step recipe on the PitchFactor's end.  I had forgotten just how powerful and capable the SoftStep foot controller is.  You have plenty of options to achieve exactly what you want, once I'm sure that the direct routing will work (or that you have the Expander option).

As general examples, the PF will respond to Pitch Bend messages, or CC from 0-99.  You'll be able to set the range limits (half / whole step; octaves) on either the SoftStep XMT side, or the PitchFactor's RCV end.  The PF has MIDI Learn.  You have a variety of algorithms to choose from for pitch-bending, and can variably glide or hard-snap to pitch.  And, with two independent pitch shifters, it's possible to bend two intervals at once, land on 'blue' notes, fade or switch between targeted pitches, etc.