I Can and have been under all of them. They are very clean pull outs .. What ever happened it was fast! Sharp fast ductile holes.
What should i do about the 3/4 plywood ?
Overdrill the holes, let the wood dry out well (since the boat was found drifting with these holes) and fill with epoxy, then redrill to appropriate size. MainSail has an excellent photo description of a good way to do this at:
Re-Bedding Hardware Photo Gallery by Maine Sailing at pbase.com
I would be concerned about the deck in these areas even if it looks like fairly clean holes. I agree with BadSanta that putting a few layers of glass along the bottom side is a good idea, along with a good backing plate of a solid material.