Isn’t this kinda what Trapcode Sound Keys does? I could be wrong on that. I haven’t used it in a while.
It looks like, if i’m following what you’re doing right, you’ll lose the keyframes with every new audio track. Which means you’ll have to regenerate them, then re pickwhip them. So, really, no efficiency gained.
Now if you were pick-whiping pre-comps, the comps should all follow the new keyframed layer. You would have to turn those “5,7,8,11,14 “ layers into pre comps. That’s actually what I’d try to do first. I have less problems with pick whips forgetting what the parent layer was doing that way.
-dl