Alas, the rebuilding and refilling of the coolant system resulted in another setback. The water pump itself was leaking through the main gasket. Result? The cooling system had to be re-drained and torn down again, which reflooded the valley of the block with coolant.
The pump is in shambles. All five of the back bolts were rusted. One seized and snapped in half. It would be kind to call the gasket "rotten." Everything will have to be replaced.
To add insult to injury, a tension bolt for the A/C pulley bracket managed to strip the mounting hole inside the engine block. Looks like I'm going to learn the fine art of TimeSerts too...