metal in oil pan

I would think if any of those pieces you showed us were part of piston rings that you would see and hear the problems. Somewhere along the way that engine was in a vehicle that was hit hard in the front, odds are good that something busted during that impact. During impact parts may have broken and then found there way into the pan. It also could have happened as a result of somebody doing a botched repair on the front of the engine after the accident. Did the car have good oil pressure, compression? Did you find any tiny metal particles? I`m guessing the rotating assembly is okay but if you`ve got it down this far? It`s up to your wallet.