I believe those magnets you are indicating on the 28mm optical housing interact with the electromagnets on the face of the sensor assembly. The orange plate with wire traces on all four corners. I agree with your assessment that the 56mm lens is just a focusing voice coil and is not stabilized.
Also, are these sensors 6mm diagonal? (1/3-inch sensors)
Is there any chance anybody can take calipers to both lens assemblies and find us an actual height?