The black box that is making noise is called a DISA flap. You should replace it. The part number is: 11-6-17-544-805. When you take it out you'll see that the flap is most likely separated.
The squealing is hard to isolate on the video. You replaced all pulleys? Sounds like a deflection pulley or alternator. You can use a long screwdriver as a stethoscope to isolate.