You need to use Vault skill inside combat with Demon King when she's erect to get an Ouroboros ending.
Defeat spare is probably for spare virginity option, when you come anally virgin. It was added not long ago.
Sign Girl option is a story mode scenario. It happens when you return to town shop in first town of story mode, peek on her underwear, compliment it, and she suggests trying it.
Brigand Horny cant is probably a left over scene. I don't think horny type of Brigand has anything related to cant. You can talk cant with Brigand Cottage and you have a special scene if you're horny (lusty), bit that's not it.
Angel pacifist is probably broken, if I'm not mistaken. I mean, to win Angel combat the way of pacifism you need to lose all of your stability. When you fall, you need to be face up, and she ends the combat. But the game doesn't register it as winning through pacifism actually.
Fire Elemental resistant: get Alma as your companion, ask her in your camp for a Boon. Then meet Fire Elemental while being a slut, choose to have sex, choose missionary option, and she will ask how hot of a finish you want. Choose the hottest, lava.
Lemon King is a April fools easter egg. You probably need to change the system time. It's right when you meet her.
You need to remove all the things you wear on your legs and backdoor and then fight the Dark Knight. If she goes Haymaker, she will finish you with scrambled eggs.
You need to place portal on a Ring Gag with the help of blacksmith or second town store. Then you need to camp and probably rest there.
Idk what's with werewolf battle. You probably just need her to fuck you and knot you.
Idk how to starve with Naga cave-in. You probably need to lose her battle with 0 food or even 0 health. And be sure you have manual checks fail in options. Just in case.
Never saw Kylira actually being a healer. Maybe it's a story mode scenario. You meet them as healer. Idk