Sounds like you might have two different issues here. As you probably know, the locks are operated by vacuum rather than the typical electric actuator. My guess is you pinched, cracked, or snapped a line in the driver's door which is causing the whole system to lose vaccum pressure. The lines are small hard yellow plastic and are fairly unflexible and brittle. Take the door apart and see.

As for the lighting / seat issues this is the result of a failed seat belt relay. My car had (still has) this problem (1995 E320) I'm sure its the same for you. On my car (w124) the relay is located behind the instrument cluster, $60. Check the contact switch out on the driver's door just to be sure that's not the problem (swap it with another from any other door--easy) The seat belt relay makes the red fasten seat belt warning come on when a door is open. On the driver's side, it also gives power to the contact switches making the lights come on, the seat work, etc. Same as my car. That's why they work with the pass door open, which has an independent circuit.

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2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro