1)Death gods have no business with the living. If she knows death gods, she knows this. If she doesnt, she would have no reason to fear Gard specifically over Molly, the girl with green fire anima banners and All The Eyes.
2)Eldest Ankou is of Winter, sworn to Mab. She's both the daughter of a death god and a Changeling.
We explicitly noted this when we met her.
3)This is the Dresdenverse; Power is Power is Power. Dresden didnt go to school to learn how to use Hellfire, or Soulfire, or the Winter Knight Mantle. The Capriocorpus didnt need a whole song and dance to go from using human magic to using ghost magic. Molly didnt need a university course on becoming Winter Lady. Neither did Lily.
The Kemmlerites did not expect to need an instruction manual if their Ascension ritual had worked and made one of them a god.
1) the whole point I was making is that if a Chooser of the Slain shows up that's a strong sign you might shortly be one of the slain, even if they're not the one doing the slaying.
2) Molly didn't use the Crown on her, so all she has is suppositions based on knowledge pre-dating the existence of both fey and Changelings.
3) Completely wrong. Kumori makes the very explicit point that necromancy uses a different energy to regular mortal magic, and so it has different effects on its users. Similarly, the reason other supernaturals can break the Laws of Magic without it backfiring and twisting them is that the energy source they use is different, and doesn't rebel like the life based magic of mortal magic when used to do things antithetical to it.
Whatever the Dark Hallow would have made the ascending Kemmlerite would have had the power of a god, I don't think we were told it would make them divine, or into an actual god. Presumably they'd still be running off necromantic/death energy given they'd be empowered by eating a bunch of ghosts.
Mab says 'The heir would gain power such as has not been wielded by mortal hands in the memory of your race.'
Dresden replies 'The Darkhallow. That's what it is. A ritual, tomorrow night. Halloween. They all want to be the one to make themselves into a junior-league god.'
But at this point Dresden doesn't really know what a food is. He's using imprecise language, using god to describe power level. Note that it explicitly would put the power into mortal hands, not immortal ones, like those of a god.
Note Mab, the Erlking etc aren't gods. The gods, according to a WoJ, existed before time did, and the likes of Mab are immortal bearers of mantles but they're ascended mortals who can into existence after time began.
