1. I'm not sure, haven't had one smashed all that badly yet. I believe there is a safety circuit to shut off the fuel pump. Sounds like the major problem with the starting problem is the DAS being released, not anything else really. On many of these cars, the SRS (airbag) control unit is a one-shot deal, I'm not sure about the 220 chassis. If I think of it and get time, I will research it.
1a. What the hell happened to this car?
2. No, I don't believe pulling the EIS will screw it up, should work OK.
3. I believe the PSE on a 220 is under the rear seat on the right side. Look for the plastic vacuum pipes leading to it.
4. If you leave a window open on a smartkey car, with the alarm set (doors locked), and reach in and open the door, the alarm will go off, then you can just put the key into the EIS and the alarm will stop, and the motor will start. Question #4 wasn't really posed as a question, but if that is what you are asking, I would say yes, if you break the window to get in, but the key is working, it should start. The smartkey has a metal blade to get into the car though, so I wouldn't think this should have to be done unless the central locking quit working (maybe a dead car battery) or the key took a dump or has a dead battery, AND the metal blade is missing. DOH!