Does it make sense to clay and then polish? or is clay not really needed since your going to polish (abrasive) away the surface anyway? What about a non/mild abrasive like AIO?
Nah, clay - trust me you will thank me later. It removes contaminents, not simply "cutting the head" off them leaving the bottom of the contaminent still embedded in the paint like polishing would.
It will also make the rest of your steps easier as the paintwork will be as smooth as glass, particularly polishing.
Well I've got my PC finally so I can now put in proper polishing into my 'full' routine. So it now looks something like this (insert iii, modify iv for use with PC)