Whichever '66 Bat-villain you don't think gets enough attention.
In that case I may go do this set for different characters, since for many of them I don’t have canons in all sets of categories:
sexual orientation headcanon [Louis the Lilac]: Gaaaaaaaaay gay gay gay. Kinsey 7 gay.
One Gotham slang term for gay is ‘he doesn’t hire henchgirls’, and he definitely lives up to that term. The only female henches he has are directly useful like Lila (who runs his flower shop as a cover, and I think maybe she was his sister?) or Lotus (who was a perfume expert).
gender headcanon [False-Face]: While I have my pet theory that False-Face is also most of the henchgirls, in general I consider him not to be interested in the gender binary. Most of the villains are cis but False-False is genderfluid, preferring to play male roles but always considering his gender identity to be the same as the identity he’s currently wearing. If he’s disguised as Bob, he’s male. If he’s disguised as Pam, he’s female, etc.
mental illness / neurodivergent headcanon [Joker]:
Unlike every other depiction of him, Joker is completely, utterly sane. He’s a giant troll that loves messing with the system in artfully weird ways, like Banksy with more attempted murder, though it’s usually tied to making a profit somewhere in the final steps of his scheme. Joker does it for the lulz decades before 'doing it for the lulz’ was invented as a phras.e
Sexuality-wise he’s also straight and not nearly as interested in riding the Batpole as his counterparts, but he’ll try a lot of things once.
Riddler, meanwhile, is bipolar as fuck. You can find out more in my amazing fanfiction on the subject.
3 random headcanons:
False-Face:
Literally no one knows who he is. He deliberately leaves trails that could point to possible identities, but there’s so many it’s impossible to tell. Batman’s discovered up to eight of them. He’s never stayed in captivity long enough for the mask to come off.
The plastic default mask is his casual wear outfit. He wears it when he doesn’t feel like going to the trouble of putting together a complete disguise.
He cannot stand to look at his original face for more than it takes to get a new disguise on, and no one has ever been allowed to look at it. The henches have different theories on why, and some postulate that he may have actively cut pieces off it in order to make his disguises easier to manage.
Louis the Lilac:
Courtesy of @nicow4fer , he’s got a younger pseudo-boyfriend called Dandy Lion. Dandy’s alter ego Leo is a rich boy with a fondness for clove cigarettes. He went to the same prep school as Dick Grayson and rolls in the same social circles but is very bored with them. They’re not direly in love, but they are comfortable with each other.
One of his side businesses is a queer club/bar. All the servers are drag queens, and some of his henches perform there. All the cocktails are flower themed.
He used to be a mobster in the next city over from Gotham before getting run out of town by his own gangstermates. His love for flowers started because he hid in a greenhouse belonging to a woman who was of the age to Give No Fucks. She took care of him while he was recovering and taught him about flowers, and he’s had a fondness for them ever since. She left the greenhouse to him when she died.
Joker:
His real name is Illario Bianchi.
He wears a Catholic saint medal under his shirt (you can canonically see it in 'Batman Sets The Pace’ when he’s unmasked as the fake Maharajah), but he’s not religious. It’s just a personal trinket he’s worn since he was young and he’s attached to it.
He’s got a ton of siblings, which is part of what led to his excessive need for attention
