Bearings won't freeze up just rust, and just like body rust, material is lost and there is no getting it back, even minor pitting in bearing surfaces will shorten its life quite a bit.
Good read here on water and bearings: How Water Causes Bearing Failure
You could have the heads pressure tested, and hopefully find a crack(weird to type that, lol, "hoping" to find a crack), but if you don't then what?
Visual inspection of water pump and timing chain cover, but what if nothing is seen?
Visually inspect intake manifold, it has a water jacket as well, but what if......?
And lets say you do find a crack..........is it the only one?
IMO, with the possible bearing issues and the unknown about where the water came from I would just look for a running 3.0l long block(assembled block and heads).
If you have the old head gaskets and head bolts, and intake gasket, you could reassemble the engine and then pressure test it to see if you can find the leak, you only need 15-20psi to test it, so old head gasket and 60ft/lbs on the head bolts would be fine for that, wouldn't cost anything but time.