I think that people born in hell that escape it would have different powers and requirements because they aren't dead sinners possessing their own bodies, they're people who made it to the mortal world intact and without having died a true death.
Probably closer to Wan Xian than Wan Kuei, yeah. It would fit with Molly having, in principle, her own heavenly authority.
I don't think it'd be a prayer eating thing, it seems more like it should be its own technique. Buying and selling parts of souls is distinct from receiving worship even if they're something you can mix.
That's arguable. Unbreakable Soul Bonds is very much "claim a soul of your follower as yours":
The Exalt can bond the heart and soul of a worshiper
to herself, allowing her to forever command that being's
unfailing loyalty. No torture, no drug, no blackmail can
force the target to betray the Exalt; if necessary, he will
bite off his tongue and die first. Nor will he ever cease to
love, protect, and worship the Exalt as his incarnate god.
System: This Charm can only be directed at some-
one who is a true, willing, and fervent worshiper of the
Exalt, and whose prayers the Exalt has consumed at
least 10 times with Prayer-Eating.
The Exalt comes upon her target in the midst of
devotions to her, spends 1 Essence, and makes a Will-
power roll against difficulty 4. If she accumulates three
or more successes, the target's soul is bound to her. He
now loves her unconditionally and forever; no other
power can overwrite this bond. This Charm is capable
of shattering and replacing existing powers of slavery
and obligation such as vampiric blood bonds. It lasts
for as long as the target lives, and perhaps even longer
if he lingers as a worshipful ghost.
As an aside, I sort of think you've added too many ways to get out.
Realistically, there are three ways that I described that actually lead to escape:
1) Serve Molly and she might release you
2) Physically escape - that's normal Wan Kuei method, and it's not easy with how Courts are set up
3) Go through a long period of training and enlightenment and be released. That's pretty much how "hell as rehabilitation" should work.
The other two are "die the final death" and "be hard enough that you are either a celestial exalt already, or should be" secret bonus stage. So, overall, despite flavoring, that's pretty much normal amount of ways out for a functioning rehabilitative correctional realm (i.e. hell how it should work).
One of the undersold bits of lore on the Yama Kings is that their hells started leaking souls when they attempted to dam them up to keep people forever.
Yeah, we shouldn't be doing that. There should be ways for souls to move on.
I also think it'd be worth considering what precisely should theoretically get people damned to the hell when discussing how they get out. So that we cover the basic functions that make it an afterlife rather than 'simply' a spirit world.
That's a good question. Obvious ways to get sent there after death would probably be:
1) Be Molly's worshipper- in this sense it's probably not just hell, but a general afterlife. Like Kakuri is also a paradise.
2) Be killed by Molly and deliberately sent there - that's up to us to decide with charms
When and if it starts functioning as a proper hell / afterlife integrated into reality... Well, that's a question.
I'm not convinced that part particularly matters. Anything that happens within eyeshot of us is going to be blamed on us whether it was us, was even our idea, or not. Just like how not all the fires are Harry's fault.
Odin uses undead all the time. Yes, they are sapient undead, but they are undead still. He faces no problems with anyone that we see. And Lydia does have her god father as a background on her charsheet, so I wouldn't be so sure we'll get blamed. Yes, we are the celestial exalt in the room, but she's also a semi-divine existence, who has her own thing going on.
Plus, as others have mentioned, she could also be animating wood statues.
We should just avoid reanimating anything that looks to much like a human or any classic bit of necromancy if we can at all avoid it.
I still say that we have to get the body of the Dragon our father slew. That would be a very good "big red button" for Lydia to have.