1: The oil pressure sender is pretty famous for taking a dump. It is electronic and over time, they fail and wear out. That should be your first replacement before diving into the engine.

2: You could have a failure of the module in the instrument cluster, or you could have a broken wire or defective sensor in the front bumper area. You need to get a copy of your factory service manual and trace the wiring out.

3: See the latter part of Point #2.

4: Up is accelerate, down is decelerate, pulled towards you is resume, pushed away is cancel. Resoldering the board and replacing the electrolytic capacitors will restore functionality is many cases.

5: You could have problems with the brushes and slip rings in the steering wheel, or you could have 2 different problems. If someone has been in the steering wheel before, they may not have reconnected the airbag.

6: Sunroof getting stuck is a very common issue. Almost always due to lack of lubrication or missing felt sliding pads. Don't force it. There is a good video series about sunroof R&R on a website called Mercedes Source .com (put that all together and that's the website).

Don't apologize for your English skills, they're a lot better than a lot of native speakers communicate on these forums!

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]