I think if it was mine, I'd pull the injectors and send them out for service. I'd fill the cylinders with diesel and let it sit for at least several days. If the oil seems a bit contaminated or foul, I'd drain the oil and fill the crankcase with diesel too, for a few days. This will soak the bearings and moving surfaces with oil and a bit of cleaner, hopefully minimizing any damage dry, rusting surfaces would produce (oil's thick, diesel's thin; easier penetrating into all the little nooks and crannies) IMO.
Turn the engine over by hand a bit and then drain all the diesel out. Flush the crank case with oil until it comes out clean (you can use cheap oil for this) and refill with very good oil. Replace the injectors and try turning her over.
You will also need to replace any rubber impellers in the system and of course, all the filters and fuel. Pump the fuel out of the system until you have new, clean diesel coming out the pipes to the injectors. I am not familiar with the trany you have so I can't make any suggestion other than using a liquid seal conditioner with a fluid change might be in order.
I believe your biggest 'if' here is going to be the rings. If they are free then you should be on your way. If not then you can do nothing more than hope that they will free up as the engine heats up.
You can probably feel if the rings are working, when the engine is running or turning over, by putting your thumb over the dip stick hole. If there is pressure pushing your thumb away, some rings are not working.
I wish you a lot of luck. Go slowly and consider what may need extra lubrication until the engine is at temperature and running smoothly.