your air bag or line is leaking somewhere\

Several possibilities; faulty / worn strut mount (upper or lower), faulty / worn control arm bushing, faulty / worn sway arm bushings or end links.
Check the 'How-To-Guides' feature on the AutoMD wesite for the specific steps to check the front end and suspension for wear. Do not overpay by $1900.00 until the exact cause of the problem is determined. Get a second, or even a third opinion / estimate as necessary.

Check the many on-line auto parts sources, such as; www.autopartswarehouse.com, www.rockauto.com,, or www.partsgeek.com - to list only a few. For example, they (RockAuto) list the front strut mount (upper) from around $58.00 (per side) and the front left or right upper control arm (includes ball joints and bushings) assembly from around $42.00 each for your vehicle.
There are less expensive means to accomplish the required repairs.

First question - how many miles driven since the springs and struts were replaced? Second question - was there a wheel alignment performed? If yes, the shop who peformed the wheel alignment should have reported and then adjusted the ride height.
Typically, the new springs and struts will 'settle' to the more standard ride height - given mileage and driving. You should expect the ride height to return to normal or new condition over a period of time.

Take it back and question them about the height. It sounds like it is too high from what you describe but there is a specification for chassis that is measured certain specific reference points. Ask the service manager to settle your concerns by showing you the spec for height and then measuring in your presence. The specs cannot lie. I already checked to see if these specs are published and they seem not to be. But this is Mercedes and they should have all the technical print to show you. You have a valid concern. print this and show it to the service manager. He will then look at you and will have to give a reasonable answer.

Coul be the weight sensors are faulty. During all wheel alignment vehicle height is also checked and adjusted to specs.

Check the many on-line parts sources; such as www.RockAuto.com, www.autopartswarehouse.com, or www.autopartsfair.com, or www.partsfair.com - for the replacement parts.
For example, they (Parts Fair) lists the front strut assemblies from around $173.00 each. The labor to replace should be around 1 hour to 1.5 hours to replace - the labor costs will vary by the individual repair shop. Be sure to have a front end alignment done when the struts are replaced.

Needs camber and toe adjustment on that particular wheel.

I would say that it is required at this point to identify the numeric fault codes that are now stored for the abs which may also cause other systems to also turn the warning lights on. Example: an abs fault on most cars will also turn on a suspension control warning light if so equipped (in this case the light is for the Electronic Stability program or ESP) and definitely the traction control light, so I believe that your problem is directly related to the abs wheel speed sensors which may have become damaged during the wheel bearing repairs. Recheck your work, read fault codes. You will need a code reader that can access MB abs system.

Check the horn buttons and horn wiring at the steering wheel - these may be corroded or out-of-position.

Remove fuse # 37 in the engine compartment fuse panel to disable the horn. This is a 20 amp fuse.

Several possibilities; low power steering fluid level, faulty / worn power steering pump, power steering pump drive belt is faulty / slipping, faulty / worn steering rack and pinion unit.

Recently I got ml500 2005 model and I experienced the same described noise, but this noise noted when stopping, shifting to D from N, shifting from D to N, run over humps, so probably it is generated from one or more supporting mounts, because I changed the rear brake discs and pads, but I’m still living with this noise … I’m going to the workshop when I get a chance …

What is the wrong fluid? If it needs to be flushed or removed - simply loosen and remove the return hose connection and drain the fluid into an oil drain pan - when cranking the engine momentarily to operate the steering pump.