Very, very lucky,,,,,in 18 years I have only seen one motor that popped a freeze plug and not hurt the block or manifold .!!!

Really? I did this and mine never got hot or anything,

The problem is now that I do not really trust the boat. To really get my confidence back, the engine should come out and the flywheel removed to inspect the three casting plugs behind it. (And really to see if a crack is hidden somewhere.)

And there are a few leaks here and there. One behind the starter that is intermittent, and a couple from the manifold on the port side, and the riser gasket is weeping. (easy fix)

How the heck does a guy mess up a winterization? It's not hard. Pull the plugs, drain all the water out. Put the plugs back in and suck up 5-6 gallons of pink rv antifreeze. Done.