You are correct about the AOA vane, but the fact that it was changed out and the problem remained indicates it likely was not a factor. Using the pitot static test boxes with hydraulic and electrical power on the aircraft and with the squat switch bypassed (so the aircraft does not think it is on the ground) you can apply what ever pitot and static pressure you want to mimic the speed and altitude the problem occurred and go from there. You could also move the AOA vane to generate an input from the vane into the control system. I would want a Boeing engineer on the phone while doing these tests but something definitive should have been found and corrected before releasing the aircraft for a test flight, never mind one with passengers on board.