backstory brainstorming session

[beforethepunchline]

So Bombshells: United is coming to an end without any actual appearances by Harley Quinn. On one hand, this gives me absolute free rein with her backstory, which is great. On the other, it gives me absolute free rein with her backstory, which is horrible. I wanted it given to me in the comics, gdi. So I'm opening this up to you guys for help brainstorming the finer points of her story. Because, yeah, I could just play it without one, but I like to have one in my head even if it never comes up in-game. I'm just much more comfortable that way.

Here's what we know:

• Harley is English but was sent away to attend charm school in America (we see her refer to the Depression and end up in Louisiana, which support the notion that her charm school was not in her home country).
• There (WHILE STILL A TEENAGER, RED FLAG ALERT), she meets Mistah J, who sweeps her off her feet and into a life of crime.
• The crime is fine by Harley, but Mistah J starts experimenting with something else, dark magic, that scares her off; he finds Batgirl, here a vampire, and "she did something to him so...he was never really my man again" (turned him? Is the Joker a vampire in Bombshells???). Harley leaves, telling Pam that she knew there were monsters in the world, but that she would never be one.
• At some point she returns to England, gets her degrees, and becomes a licensed psychiatrist at Arkham Asylum in London.
• We DO see her wearing the white greasepaint throughout her flashbacks with Mistah J, so we can assume that this is part of her bank-robbing costume somehow.
• However, in her first appearance in the series, it seems to appear spontaneously when she snaps and changes from Harleen to Harley, as signified by the change in hair, makeup, and attitude.
• Harley, while traditionally written without superpowers, definitely has them in Bombshells. She is able to turn anything into comedy, which allows her to break the fourth wall and bend the laws of nature. Birds will fly around her head if she's dizzy. She can produce a mallet from nowhere. If it's funny, she can do it.

Here's what I don't know:

• Where does the white greasepaint come from? Is this an actual transformation? If so, what caused it?
• Did Harley always have powers or did they come from the same place as the whole Harley Quinn Look?

Here are some more thoughts I have:

• I think Harley can change back to Harleen at will, but there is definitely some kind of transformation happening here. I just don't know what caused it originally.
• At this point in Darrow, she's still Harley because she wants to be. She may eventually change back and forth like a superhero and their alter ego, which I think is something sometimes seen in other Harley Quinn incarnations and which I'd like to play with eventually. But right now, she just wants to be Harley, and she seems, in canon, to be more comfortably herself that way, electing to stay as Harley even after they stop the Joker's Daughter from possessing Pamela.
• Maybe something happened in the bayou while Mistah J was conjuring up potions and elixirs that caused this change in Harley? Because originally, when they're just robbing banks, it could easily just be a disguise, but it's no longer that by the time she's working at Arkham. (See 1 and 2.) Something equivalent to the traditional vat of acid, like she mistakenly takes one of the potions or is coerced to do so?

Ultimately, it'll come down to what I decide suits my interpretation best, but I could really use people to bounce ideas off of and outside input, because there may be some great possibilities I just haven't thought of or flaws in my logic that I haven't yet seen. I can't find any real sources regarding her background from the creators, probably because, I assume, Bennett would have revisited this backstory at some point if the series weren't being canceled, but if you know of any, I'd love to see them. Help please!