Dedicated line question

At the very least a unique breaker & wire.
On the phase with fewest or no motors.

Required or recommended? What is it? 

The primary intent of a dedicated line in audio is to allow nothing else on the line to add noise on the line. Having a separate breaker helps the separation. Also, not having all that extra wire strung all over the place allows less picking up of stray emf. 
Is this a audio noise concern or capacity issue?

Sorry the question I
is focused purely on electrical draw. I’m aware of all the preferences around noise etc. this is just my lack of knowledge of electrical. I’m guessing if nothing else is ever drawing current on the other outlets and I’m supposed to have a dedicated line that from a pure power pull perspective it’s no different ?

Yes. If its on the same circuit as another item then it is not a dedicated line, is it? It's a shared line.