I would not wish to stand in the way of the data being made available to the researchers but I am unclear why they with to use such a complex control strategy: “there may be as many as three sources of controls, prospective concurrent controls, retrospective controls, and historical controls or LimiFlex subjects.” 
Earlier they state that “This is a multi-center, prospective, concurrently controlled, non-blinded study. Balance between groups will be achieved through sub classification using propensity scores.”  A standard form of randomized allocation would be  preferable in my view.