Currently if you have a multi loaded with each track for midi input, and you only use a few, Freezing the whole group of tracks doesnt remove the instrument.
For example. A multi of sustains (voilin, voilin2, viola, cello, bass)[Track preset]
I record on voilin and cello and freeze the whole sustain tracks. it keeps the voilin 2, viola and bass as instrument track and doesnt remove kontakt instance. Manualy disabling those tracks does disable the instrument.