Had my 230k for two years now. Had all those faults and initially they all frightened the crap out of me as the Mercedes systems are / were new to me. Just done a brake switch today as the ABS / BAS light was on dash and that fixed it. This also affected the Cruise Control too (had stopped now working).
A check on Star at an auto electrician near me (Sheffield) is £30. This really is needed to find out what is going on. These cars are a nightmare as they can have idiosyncracies that will fox you if not used to them.
The roof module went on mine before i bought it. Found out afterwards, ofcourse. It's a fuss of a job but I managed it with a few hours cramped in the boot dismantling everything to swap over. I picked up a warranted second hand unit for £100 on Ebay. Mercedes wanted £1100 to supply and fit.
I find Mercedes dealiership to offer very poor service. They never return calls. I'm still waiting for a call back from a technician from Monday morning to query a fault. I've rang twice but still no response. I even made an appointment by phone to have Star check done, got down there and they told me that they had no record of the call and could not help as they were busy.
These cars are a bit like Landrovers. You need to be prepared to get your hands dirty / busy, or pay someone else that will at a cost. Fortunately i've had a Defender for 10 years so am used to both.
Good luck