Autumngossamer - Honeystorm
Hard Mode: Sun God. I could see a very Hades and Persephone relationship. In a darker AU her stunt at the gathering could have gone wrong without Selene's support and instead Autumn was sacrificed and forced to serve the Sun God for all eternity. But since she's the only mortal that could best him I think he could have fallen in love with that kind of power. I could imagine their story to be an allegory for relationship abuse. No matter how many times she finds a way to leave and reincarnate herself, fate brings her back to her abuser, but is it chance or his manipulation or her illusion of dependency on him.
Easy Mode: Hotspring Boys at The Temple. Yeah I don't know what to call them, but all of them paired with her. They just couldn't stop seeing her and still sneak her back just to cuddle, but then always get in serious trouble every time, but neither of them can help it. Then they somehow could have kits with Gingersnap and then they gotta all go on trial for breaking the laws of the astral planes where they decide Ginger has to be dead. Then it can turn Spirited Away where Gingersnap manages to escape back to the land of the living, but is fading away. She learns that if she eats food it keeps her from fading, but if she goes hungry for too long she'll return back to the trial. Not only that, but her kits are incredibly sickly, half dead from being born of someone with half life and half dead.
Hard Mode: Brakewings. Kind of a weird relationship where he totally falls in love with his teacher, but I imagine it's very one sided where only Fairytale has feelings for Brakewings. Fairytale would do everything Brakewings tells him, believing that they'll be able to work together, that he'll be able to achieve his dreams. When he's wounded and Brakewings tells him he can't be a medicine cat I imagine the love sours and he uses his passion and anger to sabotage Brakewings life. Framing him as the one for unleashing the curse, framing him as intentionally getting rid of his sister and overall turning into a psychotic lover.
Duskslayer - honeystorm
Hard Mode: Foxbane. A really bad romance, I'd imagine that Foxbane would see potential in the way he can convince anyone of his emotions and how his mothers are three of the most strongest she-cats in the forest. I think she would start training him as an apprentice to spy, force him to kill, and learn how to control him when he "goes dark," while also ensuring he keeps a strong family connection with his moms to keep them in control. She would probably arrange herself in a marriage with Duskslayer just so she has control of him and therefore Innocentia, Shule, and Glow. He probably would never understand what real love is and growing up beside Foxbane believe that everyone's faking their emotions like her and him. I think even in this AU he would meet someone like Unseenlight's who would lead him back into the path of good when he can see through the lies he's been told.
Hard Mode: Omega. She would probably join Fire Gang as she did, except when she'd try to leave it he wouldn't allow her to. Instead he'd want to keep her because if he hurts her then he gets to hurt Littlestar and according to Innocentia she tastes good. Arctic would probably try to pray for the Sun Gods guidance, but Omega would likely put her down for trying to pray for someone like him. The longer she'd stay the more she'd look up to him, letting go of her beliefs because he's all she has. She'd accept it if he drew blood from her or bit into her, but I also think Omega likes the thrill of the hunt so when she simply gives in I think he'd start to give up on eating her. I imagine it would take time, but eventually the two would probably get along if both lower their claws since their personalities are alike enough for them to get along if they started out on better terms
Hard Mode: Wolfbee. She was hard on him when he was a prisoner, immediately judgmental and quick to snap at him, but over time they became friends. I could imagine that while Snowbunny was adjusting in the clan that he often depended on Wolfbee as one of his few friends he could talk to. I think it could have been interesting if they grew romantic affection towards one another while he was a prisoner, but Snowbunny was beaten for trying to associate with a WinterClan cat. After that their romance could have ended with Wolfbee staying away from him to keep him safe.
Hard Mode: Frostcloud. Originally when he was brought into WinterClan he was very violent and authoritative in the prison, but Frostcloud tied him down, depriving him of food to teach him a lesson. In an alternate universe Howlingnight could have fallen in love with her dominant personality and instead chose to pursue Frostcloud instead of Wintrystar the girl he originally joined WinterClan for. I imagine this would give Frostcloud a lot of trouble that she doesn't even want, refusing any of Howlingnight's advances, but Wintrystar doesn't buy that Frost isn't really in love with him. I think it would be gory, but also comical how possessive Wintrystar could have become of Howlingnight and how downright horrified Frostcloud would be trying to push Howlingnight away xD
Easy Mode: Funk E'tan. The most dangerous AU on Classic. I imagine that it could have happened while they were planning the wedding where Funk and Sean both kiss. But Sean's honest and immediately decides he needs to tell Shule right away, but Funk isn't dying a second time and that's how Sean gets stuck in the league. So on top of a wedding where they both messed up they have the Regime trying to get Sean back and then Sean and Funk trying to deal with their feelings, but now Funk created a situation where he literally trapped himself with Sean so it's hard to not act on those feelings. I imagine that Funk and Sean would come clean in the end and that Fox, Glow, and Shule would nod in understanding, but then Funk and Sean would absolutely wake up to some horrifying murderous lair xD
Hard Mode: Deal. I think a cute AU would be that instead of Deal finding Glowstar when escaping from SunClan he finds Sean. Sean would watch out for him and thanks to them living in tunnels Foxbane would never be able to stop Sean because we all know that tunnels are Foxbane's only natural predator. I imagine Sean would start out as a supportive friend trying to keep his friend safe from an abusive relationship that eventually blossoms naturally into a relationship.
Innocentia - stardance
Hard Mode: Omega. I imagine the two as just a fun duo who act the most immature together. Really I don't think it would change too much from their friendship, they both seem most comfortable when they're just out causing violence. I think sometimes they can have romantic gestures, but for the most part they show their love through the adventures they have together.
Misty Rose - racer
Hard Mode: Littlestar. Anytime Littlestar's in danger Misty's the shadowy hero that helps her out. I think their romantic relationship would never be public. But I could imagine that if they were out of an herb Misty would leave it at the border for them, if someone ran away Littlestar would find the culprit tied at the border. Misty would never get the affectionate reward she craves, but loves Littlestar so much that she'll always help her for the love, never a reward. (Yeah that's right Jetclaw, you think you can steal Flamingstar, I'll ship as much as I want with Littlestar! xD)