Great question. Your LLPP will have a higher priority unless you are entering a LLMP attraction during a LLMP return window that you have booked or added by usage.
Does that make sense?
Dave
To confirm what @Dave006 said: we had both the LLPP and the LLMP for the same park on the same day, and the LLMP would take precedence if we tapped in to a queue during the return time window shown on the LLMP pass (so LLMP would be used, not the LLPP).
Any other time (if outside of the LLMP return window), then the LLPP would be used.
Said another way, the LLMP will have higher priority than the LLPP if you are tapping in for the ride during the LLMP return time.
We confirmed this with Guest Services, and through our own experience.