For the technical questions on bearings & shock replacement I am no expert. Ask a good M-B technician, either on this site or in person.
Even if I were an expert, I think that the noise would be best diagnosed by a good, experienced chassis/drivetrain technician in person.
I had bad front wheel bearings on my 240D, and I thought it was loud tread design on my tires. It was a humming/thrumming that increased in volume with speed.
But that was a 240D and you have a 4WD Ml model.
Had a bad front-wheel drive front hub go south on our Olds, also. It was a similar noise, but I could only hear it on smooth pavement. It was insignificant and even hardly perceptible to my wife, but I knew something was wrong. I took it to a very good transmission guy and he drove it. The first thing he did was say "it's not the trans". Then he steered it hard left & right at about 40 mph. The noise got louder going left. He said " Your right hub has gone bad". He was right.
Take the ML to a good chassis or front-end shop and have them drive it.

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Now you're suckin' Diesel!

'88 300SEL
'92 300D 2.5 Turbo
'96 Lincoln Town Car. The Jazzmobile.