Mira, not to be rude, but you are being stubborn. Didymos has shown you evidence, and you are refusing it because it doesn't line up with your theory. Sorry, but you're wrong.
As for the whole Bob doesn't know everything...Harry's opinion on Bob is subjective, not objective. So Harry could be wrong about Bob, according to you logic. See the issue?
Besides which that was just poor writing on Jim's part. I have pointed it out before but the "revelation" about Soulfire that Harry has in Cold Days is almost exactly the same as Bob's explanation of it to him in Small Favor when he first gets it. I know Jim gets to read several different versions of each book so he forgets sometimes what he has written, and is often very busy both professionally and personally (he is only human after all) but nonetheless, it was almost a flat out error. But I love his work, so I make it work in my head. But looking at it dispassionately it is poor form.
So to repeat:
Immortals are qualitatively different from mortals. They can only be truly killed in certain places in space (Chicago-above-Chicago) and time (conjunctions - Halloween). They are not the same as the Elves of middle-earth, although normal Fae might be similar. Immortals like Hades, Mab, the Mothers, Angels and the Ladies can be burned, chopped up or shot etc but will always reform, unless killed in those specific circumstances mentioned above. Then the actual holder of the mantle changes, and the mantle can be consumed. That's the whole plot of Summer Knight, trying to absorb the energy of the Knight to unbalance the Courts. And is also what Bob talks about when he is explaining his secret in Cold Days, that this is how Immortals feed/run free. That was why Bob's information was so dangerous it warranted his destruction.