I've read the whole thread, but may have missed it.
You haven't said if there was any visible damage to the turbine, compressor, or excessive play in the shaft.
There is no way that was ingested in the up pipe as you would have compressor damage, along with intake valve and possible piston damage.
I would say do a compression test to verify no bent intake valves, but if you don't have compressor damage [that washer or whatever it is wouldn't make it through without obvious damage to the wheel] you're likely fine in that area.
I will say it looks like it should be round and hit something that put it in that shape. But if you're leaking oil in the I/C why bother putting a hurt turbo back on.
I would look at the compressor and turbine for damage and/or housing contact and have it rebuilt if no damage has been done to the wheels or housing yet.