The function "Freeze" is a switching function - on/off, no continuous controller. If you connect an expression pedal to the Remote and "misconfigure" it as Mono Switch and assign "Freeze" to it (might still appear as "Hold" in the menu) you can somehow switch on/off with the pedal, but the function is latching. Not really practical.
This is kind of what I need. I just find it a bit nicer to roll a pedal to initiate the hold instead of a switch which just seems a bit alien to me. This is how I used to set up my Axe FX, dare I say it, and it just works, IMO. I understand that it's contrary to the way pedals like the Superego and EHX Freeze work (with switches).
If you intend to control the same effect like "Freeze" continuously via pedal, I would configure the pedal as Morph Pedal, morph the Mix of the delay down to 0% (while option "Mix: Pre" is selected) and at the same time morph Feedback up to 100%.
This will create a different kind of effect, but I'd be interested to try it. Thanks!