[Lee]

Yes, for the purposes of the question, the assumption was they had already acquired said powers, and it was the act of losing the powers themselves that would kill them, rather than conditional deaths.

Deadman was indeed on the list! (I'm not as knowledgeable with Spawn; I thought he just clawed his way out of Hell, or something like that?) Deadpool, who I do count as a hero for this question because it still applied during his brief stint as one (he did make the Avengers, even, at one point). Wolverine was, as well. The adamantium would eventually poison him, and even if it didn't, the weight would slowly crush his diaphragm and cause microfractures throughout his bone structure. Cable would die, too, because of the TO virus, depending on where in his life we're looking. Spirit was my final choice, for the same reason as Deadman.

Did that address all issues?