Looks like you are referring to parameters defined inside the prediction model/state function of the MPC controller. You can make these variables parameters/arguments to the state function by following the guidelines on this page.
To use MPC for static optimization, one idea is to use the parameter as an MV and set a MVRate constraint to zero. That would basically make this MV constant. That way you could have both dynamically changing MVs and a constant one. If you try it, please let me know if it works.
