Unmix drums would work to separate kick, snare, toms, hats, cymbals, room/noise to different layers.
It would be good if the algorithm was as non destructive to transients for each separated element, and I think this could be done by smart-complex transient crossovers with a user controlled variable. For example, if a kick, a snare, and a tom all hit at once, each would have a blend of each others transient ranges.
Unmix Notation/Range would have two modes,
-complete frequency-notation separation to individual layers (with harmonics/and or synthetic harmonic reduplication?)
-Ranges - by octave, or, a “smart” mode. Smart would essentially figure out how many/different instrumentation ranges there are and separate them.