Incase anyone else is searching for a solution, I think I found one. I am knew to the production suite software so it may not work or may depend on your project, but I am going to try adding markers to my song in Soundbooth, and then put it back into Ae and hope those markers turn into layer markers.
In Sb, somehow I found a menu that gave keyboard shortcuts for both numeric keypads and non-numeric. For this specific task (adding markers) it’s “m”, or “shift+8”. Hopefully this works!
Just saying since cueing motion to audio is pretty important and all the keystrokes suggested just made my RAM preview stop playing in Ae, my keys are pretty preoccupied already, I don’t think I have KeyUp, I don’t have an iPhone, and I already carry plenty so I don’t want to add an external keyboard to the mix.
I hope this works!