1. Yes, vacuum tube detached, re-attached and solved problem. On other occasion the vacuum pump had to be rebuilt because the diaphragm had a hole in it.
2. Yes, didn't even attempt to repair all leaks, plugged at source.
3. No, but I have the pencil type glow plug upgrade, new starter, battery and alternator.
4. Yes, oil filter pump housing gasket. I just tightened four of five and leak lessened. See number 9 for reason the fifth bolt is damaged enough to prevent removal of filter housing. I bought the gaskets to replace them but fifth bolt was damaged when drivetrain shifted forward when motor mounts and tranny mount disintegrated in a 8mph rear-ender with a Jaguar. Head was bent just enough to keep allen wrench from getting enough traction to remove it.
5. Not that I'm aware.
6. No, but I did have to lube the hood release mechanism and cable with PB Blaster.
7. Yes, so I disabled contraption on valve cover and shift manually now.
8. Yes, if you mean the plastic mounted bolt that attaches to intake manifold. One is off.
9. Not any more. All three rubber mounts disintegrated in collision. I had to reattach driveline to tranny and couldn't drive it home from a 8mph wreck. Absolutely no body damage whatsoever. Cracked top of radiator, bent throttle linkage, bent bolt head on oil filter housing, detached several vacuum lines.
10. Yes. Replaced all rubber bushings, tie-rods and ends, steering damper, adjusted steering box(needs it again after six weeks). Too loose for my taste still.
11. Yes, occasionally. Usually if wheel is slightly turned right or left when parked I will get this issue. I just push the wheel toward the straight ahead position and it will usually turn with no further problems.

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1993 W124 300D
-297K on the clock as I type this.