Hydrolock would have done things like popping the tops out of pistons or heads, bent/broken rods from the sudden stop, and other sudden stop problems, like a twisted crank.

Broken/bent valves is usually FOD or piston contact, unicylinder valve damage is usually FOD, multicylinder is piston contact, most often from a broken/jumped timing belt.

I confess that I'm not sold on the new belt tensioner system. The old spring loaded tensioner pulley seemed to work fine as long as the bearing in the pulley held up.

I would see if the heads can be repaired with new guides and valves and a touch of combustion chamber cleanup on the nicks if any, perhaps new valve seats, and you get the new valve stem seals and updated guides in the deal. This should not be terribly expensive, add a head set, timing belt and new idler pulleys and tensioner set, new front main seal, water pump, and you are set to go.