I can only be of minor help.
The wires at the Old Alternator connector: The circuit connected to the 2 Fat Red ones end up going to the Battery +, I do not know why there is 2 of them.
The siknny Purple wire ends up going to the Charging light in the Dash Board.
There is no Ground Wire of anysort down by the starter; I was also told by some Members that Ground wires on Mercedes are Brown or could be Brown with another color strip on them.
On mine in the image below the White and Purple Wire on the terminal by themselves. The white wire goes down the the Starter Solenoid and when the Key is in the start position carries the + current to that Purple wire that is under it. The Purple wire goes to the Glow Plug Ralay so that your Glow Plugs get + current while the starter is cranking.
