“I wonder if implosion at this depth and pressure even leaves recognizable bodies for retrieval and burial?”
There were no bodies left after the Thresher implosion nor the Scorpion loss.
The theory is that at that depth and pressure, bodies are immediately vaporized. In other words, there is nothing left to retrieve.
Pressure is .433 pounds per foot. At 12, 500 feet, 6, 000 PSI. At that pressure it takes 2 nanoseconds to implode and 4 nanoseconds for the body to sense pain. Thankfully, the crew did not have time to sense a problem.
Nanoseconds is a lot shorter than an implosion. Milliseconds is what you are looking for.