Eh, close enough. Big difference is that a sin-eater is vastly more powerful than a werewolf. It's one of top three favorite official splats, the others being Werewolf and Changeling, so I recommend looking into it.
That is an awful name and whoever came up with it should be slapped about the face with a large trout. That said, a Story-Telling system game without a morality system in place... Hmm... I can't decide if I like that or not. I guess it depends on whether it fits with the theme of the rest of the game. Automatic successes on guns seems a tad over-the-top, though.
Eh, I'm in it less for the immortal schemers part (Mage, Changeling (sort of), Vampire, Leviathan if you're willing to go outside official games can all do that, as you said) and more for the whole Egyptian mythology motif. Fascinating subject, Egyptian mythology, and I'm looking forward to seeing the finished product.
Oh, I doubt they're intentionally having bad things happen to them. That said, I find it morbidly amusing that bad things keep happening to delay the release of a game with "Curse" explicitly in the title.