Add second smart thermostat to same room with UFH


I use Tado with an extension kit to control my rads and hot water. I also have wet UFH in an extension which I want to add to my tado system.

First - if I have a standard non-smart UFH controller with a wired thermostat, can I just replace the existing wired thermostat with a tado smart thermostat? And assign that thermostat as a new room so I can set schedules for it (and leave the non-smart UFH controller permanently on so it is effectively controlled by the Tado thermostat)

Second - the wired thermostat is in a really silly position. To save messy rewiring, could I get a second thermostat (either another smart thermostat or the new wireless temperature sensor, as far as I can tell it would make no difference), assign it to the same room as the wired thermostat, and set the wireless one as the measuring device? I'm hoping that would mean that the wireless one became the controller, but what I am worried about is would the one that is wired in would still trigger the UFH on and off? Or would it behave as if it was completely redundant?

Would that work or is there anything I haven't thought of?