Jim has already answered those questions.1
Neither of those address the questions at hand explicitly enough, apparently. [i/]I[/i] feel like the issue is pretty clear, but it hasn't stopped literally
years
of back and forth on the issue and it just keeps popping up.
He talks about how there's not really a king of summer/winter, but doesn't address the nature mantle of the Erlking specifically, he doesn't remark on whether it's a discrete thing in an of itself or if the Erlking is just a beefed up Sidhe.
I don't think that it is necessarily the same kind of thing, that it wouldn't just hop to another vessel.
In the second quote Jim starts at one place and ends at another. Like I said, I though the meaning was clear, but apparently it's not enough.
Someone just needs to ask "During the Darkhallow, would the Erlking have gotten sucked up and eaten along with all his power/mantle?" and "Do all mantle act like the Queens' mantle where they are independent things, that jump to a new vessel when the old one dies?".