Engine failure after oil change

I got the engine and transmission out pretty easily for the first time I've ever done it. Opened the oil pan and found the remains of the bearings for connecting rods 1 and 2, as well as several pieces of material I can't identify. Anyone recognize what these pieces are from( the third picture)? Part of a tappet?

The connecting rod bearings for number 1 and 2 were dry as a bone, as was the counterweights in that section (fourth picture). I will have to look for the reason for that.

I will have to see what the machine shop says about if the crankshaft is salvageable. Any thoughts?