Every GM is free to change/interpret the rules however they wish. I tend to operate a three step pattern for dealing with uncertainty.
1) If you can't prove me wrong in under five minutes, then the rule doesn't exist and I get to decide.
2) If I make a ruling, it is absolute even if it's not in my favour and will not change for the rest of the session.
3) If you can prove I was wrong and I agree or I find reasons to do so, then I may change my mind at the start of the next session otherwise it remains true at my table for as long as anyone of us remembers it.
I don't think "Asmodeus" is part of the Product Identity, a quick search on Wikipedia suggest the name at least originates from a source that is out of copyright.
The details of the Cult of Asmodeus as laid out in Faiths of Corruption would count, I imagine. You might be better inventing your own based on the original (or one of the more modern, 17th century references).
She's a woman living in a pseudo-medieval town. If a real woman wore that in the Medieval era, she'd be raped or beaten.
A real woman in the medieval era would not be able to set men on fire for trying. The setting may be medieval but the social politics have always been more modern.
Frankly the problem with what you're saying here is that you seem to feel that women should only be shown trying to be attractive if they are desperate for a man. There are plenty of people out there in the world beyond your front door who would wear an outfit like that and not think it was obscene. (Most of them would be women).
Is it wrong for a woman to be comfortable dressing how she likes when she has the power to roast men alive?
The problem, in general, is that artists think it's okay to objectify women in the very center of the cover of a product that is not specifically a porn magazine. This is never done to illustrated men in RPG products. It is always done to women.