I definitely want to get to the bottom of it but also haven't ruled out parting it.
This is my first etec so don't know a lot about the injectors. What is involved with monitoring them? I ruled out the injectors because of the debris in the crank. I thought is that if that cylinder leaned out, the piston would be toast with not as much debris or sludge in the crank and definitely not enough to destroy the bearing this bad. The bearing was completely destroyed, with a bit of sludge in the bottom. So my conclusion was that the bottom end failed first leading to the failure in the top end...unless there was a double failure...
But this question is what led to me hoping I could find a running engine that would include injectors to help rule out other possible issues that caused this motor to fail. And also putting in a new oil pump.
Each injector has its own flow characteristics that get measured on a test bench to determine how they need to be compensated at different rpm. The results are then used to generate a code for the ECM to make corrections which provides an equal flow between all engines. The only way I know to verify it is working as it should and within my means is to monitor exhaust gas temperature. It isn't perfect, but I find it works well with a new engine.
For the center bearing failure I think it is difficult to say, but it isn't uncommon for a center bearing to fail before any other bearing. It's been like that since the 600 HO carb which is the same engine that your E-TEC is based on, but BRP has done work on the lower end for durability. If you go with an OEM shortblock then you don't need to worry about anything from the cylinder to the base. If you want to experience the build, then you can get a good kit from MCB.
Once the engine is closed-up, make sure the oil pump is delivering oil to all 4 lines and through the oil check valves, the fuel pressure and flow is good, the exhaust valves are operating correctly, and the voltage is good. These are main operations that I focus on. It provides me with assurance over a used engine that I don't know the history. Then feed it 91/90 and hope for the best.
This is all the easy stuff. The tough work is getting the engine in without accidentally knocking the oil check valves, getting everything routed and plugged-in right, and having to diagnose any problems like an engine light for no apparent reason.