Dude, I have the MP201 and I'm using the CV outputs with a bit of resistor attenuation to keep it at the 3V max that the 'Factors want and it works great.
I was planning on using the MIDI to send specific setups to all 4 of my Factor pedals but not use the MIDI to run the expression pedal stuff.
I guess I'm just old school (real old school) but the CV stuff works really well.
You just have to make special cables to attenuate the voltage properly.
I would love to hear more about how you get the MP201 to talk to the pedals, and how I might be able to send various settings and parameter changes to them via MIDI.
There are so many undocumented (or not very well documented) features of these pedals, the possibilities are boundless if we could only get some good information.