Hello, OhSoInsane,
How did you setup finally work out? I posted the same question About the muiscom EFX 2 now I have the EFX 3 years ago but no luck. I have all 4 of the Eventide pedals and would like to do the same type of expression pedal controlling with 1 pedal controlling all 4 Eventides.
Did you try the 4 way TRS /TS Cable or splitter box where you have 1 out for the expression pedal then 4 directly into the Factor pedals?
it was good to read a fellow compsci person asking this same question.
Kevin