Need Help w/ MB issues

Hi and yes I am new to the MB world.
I bought a 2002 C240 sedan from my brother and it has a few issues that I would like to try and fix myself if possible.
The biggest issue is the Air Bags
It was wrecked in the front end and my brother bought it that way so he could fix. He re-placed the steering airbag module which I think was the only one that went off and of course the front end stuff that was damaged. The computer is reporting SRS errors and the airbag light SRS is on. Also the airbag light is on saying the passengers airbag is off. Any info on this would be great.

The other issues are smaller ones but I would like to get them all fixed eventually. See list below

SOS (Telaid) -
Can anyone tell me how and the heck you turn that off? I am assuming that it has to be turned off in the computer.

Radio-
Has poor reception and only picks up a few stations and tape is stuck in it and I cant get it out.
Can anyone tell me how to get the radio out and do I need to worry about codes if I buy a good used one from a 01 or 02 model, also will a CD changer be easy to add?

Remote/Smartkey -
The key works but the remote doesn't. I changed the batteries and I get the little red light indicating good battery but no signal.

Fog lights -
Well I have none. When they replaced the front end I have to nice empty holes. I guess that is why I get another fault on the computer every once in a while. I am planning on buying some. Are there any rules to this as far as what years fit. AMG vs non. I have also noticed there are no plugs anywhere that I can see in the front end. What color code wire or style plug should I be looking for?

Washer Fluid -
The washer pump is obviously not working because I hear and see nothing when pushed. Checked the bottle and looks like it has fluid in it although I tried to fill and water is just running out somewhere below fill??

I know this is lengthy and I do apologize for that but any info to save me time and money would be much appreciated.

John