In terms of the quotes about Nicodemus, it's obvious to me that the White God is the Enemy. What that might mean for Deirdre is unknown. Is it better than what Hades might have in mind? Your guess is as good as mine.
Oh I think that is obvious to everyone who reads the books. What that means to Deirdre is what Harry would have faced had he chosen to move on in Ghost Story, what comes next... As Uriel
told him on page 454 in Ghost Story..
"The part involving words like forever,eternity, and judgement."
Now one could argue if Nic's side wins she won't face that, but that is yet to be determined... In the meantime though, it seems like Nic and Deirdre were under the impression that she wouldn't be punished quite so harshly in Hades and would be safe from final judgement if they lose.. Seems like both feared that judgement more than anything that could happen to her soul in Hades... However
when Harry asked Hades about her, his reply was for Harry to go back and reread the classics, he also implied that she'd stay in his care in any case..
Harry concluded 349 Skin Game
I didn't know what would happen to Deirdre--but I knew she wasn't going to get off light.
The Hell of Satan and Hades controlled by Hades are two different places... Hades is the realm of the dead, all the dead travel there, a place of reward for a good life as well as a place of punishment for those who didn't live one.
Deirdre did die in the Realm of Hades, under his jurisdiction, so he gets to deal with her.... If she had died some place else, then she'd face what Uriel had told Harry... Apparently she and Nic feared the latter more than the former, they may have been wrong there...
Deirdre is Nic's daugher, Susan was Harry lover, not the same at all... Technically she was no longer Susan when Harry killed her, otherwise the reverse spell wouldn't have worked.. Deirdre was still herself when Nic killed her.