Although not clarified by Tesla, my assumption was that the four Enhanced cameras would be the three forward facing and the one now-intelligent rear camera. The four cameras mounted on the car's side would be the four added with the Self Driving option.
The email about upgrading from AP Convenience Features to Enhanced AP had additional information not in the design studio:
So now we know which 4 cameras are used by EAP:
- The main forward looking camera
- The two rear-facing side cameras
- One of the remaining forward looking cameras. (We don't know if it is the wide angle or long range camera.)