True, im not sure what effect excessively bouncing valves tends to have. I dont think they would bend though?
Im not sure how anything would get in there thats big enough to do that, I have heard of spark plugs disintegrating but im guessing that hasnt happened. Cam belt not jumped a tooth? I suppose there would probably be damage on other cylinders.
I have never had much to do with OHC hydraulic tappets/lifters, do they ever pump up and cause interference?
I would pull the piston/rod out for sure and check the ring lands/rings and the big end bearing/bolts. Then measure the deck height when its back together and compare with the other cylinders.