So Nicodemus once a year can use his Barabbas curse. He attempted to kill Dresden with it, but Shiro took Dresden's place. According to the Bible, the people had a choice. Release Jesus who had done nothing wrong, or release Barabbas, a known criminal. The people chose Barabbas. I suspect that Nicodemus is able to choose who lives, or who dies, once a year. In this situation he used it to save Blood on his soul who was smashed to paste, and should not have survived.
The Genoskwa is ridiculously powerful. Add Ursiel and he probably can't be killed outside of some very specific method. I'm saying the block squished him to paste, but he probably wasn't killed by it. Hades is a cave, and the genoskwa was very skilled with earth magic. Maybe ursiel kept him alive and he figured a way out on his own that only he could take.
Hannah is dead Because She is just a vessel for Lasciel. The coin was the special part about her. Unlike the genoskwa, she is just a person without it.
Maybe the Genoskwa gave Hades Ursiel's coin as payment to leave. Hades is a collector, after all, and his collection was just destroyed, robbed, and given away.
We don't actually know how, specifically, big... feet? can be killed. We just know valkryies and einharjar killed them. Those aren't regular opponents, like vikings. Odin and other Norse gods were probably involved.
The naagloshi couldn't really be killed either, except under certain conditions, and even then it could just be a temporary phase shift from corporeal to incorporeal until a power level or time limit is reached. The question of the day...
Who wins in a fight(with no rules because they would both cheat anyway)?
The Naagloshi or the Genoskwa? I'd love to read that!