Jack, no offense intended, but most of the time with the W124's the wheel bearings are the last source of noise. I have an 89 300E that now has 179,000 on it and I have checked the bearings twice and found that they have never needed an adjustment. If you look at those bearings, they are really "robust" as to size. In my experience (MBZ, BMW and too many Detroit Irons to mention), front wheel bearing noise gets worse as speed increases. Also ramps up when turning, especially at moderate speed. In your thorough analysis you did not mention distorted rotors. The fact that it goes away with braking points away from bearings and points to brake system. I am just trying to point you in the right direction based on 30+ years of building, repairing and the like. You asked for advice. Maybe Donnie or Steve can jump in with something better. Good luck..

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.