Hi!
Calling unregistered Clapyeron functions will likely fail as symbolics will trace down inner function calls.
Here’s a related thread about it, but using coolprop for single component systems: Media properties and component encapsulation in MTK - #7 by Sushrut_Deshpande.
A symbolic extension is being done in Clapyeron with symbolic registration of relevant functions. To make it functional though, the updates Chris mentioned are necessary.