Damage from a spun bearing will be 95% isolate to the crank, and it will be obvious. I once spun a rod bearing in a 454. It was like flipping a light switch in that car. I went from cruising 45 mph in town to it could barely push that Corvette up a very mild hill. That crank jurnal was murdered in less than a minute. It looked like a motocross track after a race. Associated damage to things that skate on oil, like cam and lifters, might also happen due to shrapnel from a spun bearing, but it shouldn't have any way to damage something like a head gasket.
I've never dealt with a broken skirt. There's obvious potential for significant cylinder wall damage. I can also see a reasonable path for a significant amount of oil to get into the cylinder an potentially cause hydraulic damage, like lifting the head and blowing the gasket, but IDK how likely that is.
It's best to diagnose before and during teardown. If you are tearing it down yourself take lots of pictures and keep everything together and in order (pistons, lifters, push rods etc). Use a sharpie and write on the parts. I suggest getting some kind of teardown tray, or you can use sturdy cardboard boxes and stab the parts into it. The main thing is organization and detail, this is not a chaotic event. Clean it up and look for obvious damages, but definitely let a machine shop do the final checks before pressing onward. It's better to sink a $100 into a magnaflux check up front than to skip it and sink $1,000 into an engine just to find a crack during assembly.
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The cylinder that ate the valve was destroyed but they had that engine torn down and back together in one Saturday. I just happened to stop by as they fired it up, so I hopped in the car with Butch, he took it slow down the road a few blocks, turned around and stabbed the pedal to the floor banging gears around 11K. That was a fun car. 