Concerning the dcxdp universe; I think there's an interesting side which is often scratched upon, but never fully discussed - the hero's apparent entitlement to information.
One fic which paints a clear image of this, imo, is "Vertical Limit", where the JL is not only hostile in some situations, but then also expects every one of their questions to be answered to their liking, offering nothing in return.
I think this idea could be interesting to explore, as Danny would already deal with this on a daily basis. The hunters in his opposition, the Red Huntress, the Fentons and the GIW, act as if they know everything about ghosts. They don't listen and they don't ask. The town's people also seem to show some bias, albeit not to the same extent as the hunters.
I just think it would be interesting to see Danny, especially in case of Ghost King!Danny, to go "No. You are not entitled to information regarding me/ my kind, you are not entitled to the business of another dimension and you may not research further against my will, unless you wanna fuck around and find out" when being interrogated by a bat, or when finding out he's being tailed by one. Or any of the JL members.
It enrages me on his behalf in many of the fics I read, so I just want to spell it out one time
Ya know, I prefer the Justice League being on the good side and genuinely doing stuff for the greater good but ya know with this interpretation of the characters I understand what you're going for.
(Also check out Vertical Limits if you havent. It's an incredible fic.)
I will say that if you're ever confused and don't know how to characterize superman or batman:
If you can't imagine that version of the character consoling a crying child, you're not writing the comic versions of the characters... and if you can't imagine them doing so, Villainize them as much as humanly possible.