1. I found it difficult at first to get used to the idea of no dipstick, but now I rather like it. I don't have to get out in the weather or look for shop towel to wipe off the dipstick. To check the oil it is in the same menu as the main odometer. The dipstick is available as a tool and costs about $70. I decided not to bother.
2. To drain the oil out the bottom you will find two belly pans. You only need to remove the rear one to access the drain plug.
3. You can get a special tool for the oil filter housing at the MB parts counter for about $10. It works great.
4. I agree with gillybenztechs answer to number 4, except in this case I would spell bunk with all caps, i.e., "BUNK." This car is under a very good warranty program. Make them fix it or replace it.