Oh ha ha
So they were in separate movie clips? That was the trick all along. Seems like cheating to me. Movie clips and graphic symbols have their own timelines so it's like using extra layers.
I thought maybe the trick was that you tweened on different layers then converted to keyframes and merged the layers.
All the same, it seems like a wasted effort when the audience can't see that it is in fact one layer. I thought the point of the collab was to show off effects that would have no reason to use more than one layer. Instead you just made a bunch of ordinary animations.