My first reaction is to withold payment and have him do as he agreed or send him on his way. At the same time, you ask about footing depth, then describe footing size. After wondering about that, I would like to know about horizontal and vertical reinforcing.
If it were my wall, I would want to have a footing placed below the local frost line, a minimum 7 inches deep and extending two inches beyond the masonry on each side. I would, for such a light wall consider a single reinforcing bar at the center of the footing cross section and extending the fool length. I would place vertical reinforcement every 24 inches to keep the masonry from overturning. How do you intend to protect the top of the masonry from water intrusion and freezing?
TB Charleston SC