I'm sorry, but that's not going to happen. I have tons of projects, and this idea would just be wasted time for me as it doesn't fit the lore at all.
The best example of succubi who turned their back on Hellish behavior are the Lunar Clan, who are pretty grey with their morality, but still have to kill humans to survive.
Example:
Almost every point you made makes no sense, like "she trying to remove the darkness from her".
If a succubus remove her "darkness", which is her body that was given by hell itself, she'll go back at being a formless, but sentient, spirit.
Elves have one in their forehead. A spirit bound to them so they don't need to worry about being pulled to heaven or hell.