OM606 fuel in oil?

[W124Pleb]

Vehicle info:
1995 E300D
OM606.910
306k miles

First post here and I'm not that mechanically literate so I'll be as concise as I can for you guys. I'm branching out here because my mechanic buddy has done an assload of work on this car, and he is at wit's end with it.

Backstory: Friend and I did the headgasket a few weeks back. Did everything the right way, took the head to a machine shop to have it resurfaced and have a GP extracted, had the valves and seats reground while it was there.. We were very meticulous about putting it back together, surfaced the block, got the timing right, used the updated MLS gasket, didn't reuse anything that we shouldn't have, etc. Started it up and it ran great, no issues, way more power than before. Awesome.

One week and <100mi later, I was driving and noticed the oil pressure drop significantly. Usually it's at the 2 mark at idle - it started dipping to 1 and slightly below. The idle surged to 1100 rpm (???) and the gauge wouldn't peg upon acceleration. I pulled over immediately and checked the oil - clear, thin, over full, and smelled like diesel! Limped it two blocks home and drained 9 quarts of this watery-thin diesel/oil mix. Also worth noting, metal flecks in the bottom of the oil pan. The first half-second or so of draining the oil it looked like silver paint - really hope my bearings aren't toast, but there is no point in being optimistic about it I guess.

The first thing I did after changing the oil was rip the plastic lid off the valve cover and check the injector return lines. Sure enough, one was weeping fuel and the end piece wasn't plugged all the way. Two of the injector ports were pooled with fuel. My initial reaction was "there's the problem", but after some consideration and googling I'm not (entirely) convinced that's how diesel was getting in my crankcase.

That was two weeks ago, been busy so I haven't driven it enough to foul up the oil or replicate the symptoms again. What I did notice today when taking it out, is the constant smell of unburned fuel in the cabin and outside the car. So I'm sure something's still up.

I'm looking for options to explore since I'm more or less gonna be troubleshooting it on my own. Could it be a bad injector pissing fuel into one of the chambers? Bad seal in the lift pump? Pump timing?

Anyway kudos if you read this far, and sorry if I sound like a mook!
Thanks guys