My dumb itafushikugi head cannons because why not:
Itadori is the most affectionate. His character is someone who is pretty considerate and emotionally mature so I think he’d be the most malleable to the other two’s needs.
Kugisaki is the most openly demanding but Itadori is a golden retriever and Fushiguro tries to be aloof while still wanting to participate. She has the easiest time directing conversations and that tends to be where she bonds with them.
Fushiguro is terrible about active participation but usually will do what the other two ask of him and they get that. He gets a bit of a pass as the worst childhood haver. Since he has whatever’s left of the Zenin clan, I imagine he provides.
Itadori and Kugisaki have the most fun on dates, usually because he will go along with whatever she asks for and she might go along with what he wants to do by the end of it. They’re both experience lovers and not Tokyo natives so there’s a lot of excitement with that. They’d fuck up a theme park so bad.
Itadori and Fushiguro is kinda just built on telepathic vibing. In canon megumi kinda broods a lot like the teen he is and he might grow out of that with time. In general he’d probably be inaffectionate emotionally but would try to compensate through unassuming actions/gift giving. Itadori would be more likely to pull him into moments knowing that. It’s real “dad will never say I love you but will bring you cut snacks” dynamic (pls ingore the family discriptors, the archetype best described Megumi’s affection imo).
Kugisaki and Fushiguro are prone to getting on each other’s nerves since they both have harsh personalities but work out best through no nonsense conversation mixed with the occasional nonverbal emotional intimacy. They’re both proud people and they get each other because of that.
Fushiguro and Kugisaki ultimately marry out of some societal obligation and it was the most sensible combination. They piss each other off during the whole wedding. Kugisaki wants a glamorous wedding and Fushiguro wants it to be done with. I think Nobara would also romanticize her love life in terms of her vanity rather than being an actual romantic, it just happens that she becomes attached to two dorks who don’t fit her image. In another world where it wasn’t the fucked up Zenin clan, they’d be the power couple of clan heads.
Itadori is the wife, end of story. That whole dress shirt flashback basically proves he’s the one that actually knows how to do housework best, probably because he had to live by himself and take care of his grandfather. Fushiguro probably would participate in things like dishes because he wants to be seen as a respectable adult. Kugisaki hates having to follow traditional gender roles so refuses to participate in them. She might do her own laundry if the clothing is important to her.
They either all share one room or each have separate rooms, heading more towards the later since the Zenin estate is empty as shit. Despite Fushiguro being the head of clan (party of 2), Maki would probably dictate the grounds the most in the end and basically have the social role of head of clan. I also half consider that they end up moving into a house more in the city since the 5 person dynamic might get awkward.
Itadori is the boyfriend when Nobara wants to have an attentive similar minded partner on SNS, Fushiguro is the boyfriend when she wants a pretty boy provider. Fushiguro acts like he doesn’t use SNS at all but is the bland feed scroller and Yuji will mainly use it to consume media but likes posting life stuff occasionally if he’s proud of something (the type to post group pics or a nice meal).
In terms of public image and general impressions; Megumi is generally seen as attractive and a sensible idea of a partner while Yuji in actuality attracts people more due to his sociable friendly nature. Megumi’s dark and mysterious facade ends up only working at a shallow level. Yuji is somewhere between delinquent and popular kid but unintentionally charms other’s through his considerate nature and ends up getting hit on the most. Nobara loud personality means she attracts a lot of attention post high school when she can wear whatever fashion she wants but equally doesn’t get hit on as much because she scares people with her assertiveness. She’s flourishes best the closer you become to her. I do think she’d charm more women on first meeting rather than men.
If Nobara seeing either of them being hit on she would be too proud to claim them but be passive aggressive about it afterwards. Yuji would mainly be amused with the most secure attachment style but might pull a move like the omake scene. Megumi would try to act unbothered but might eventually fold if it ticks him off enough.
If Yuji is hit on around the other two, he would be direct about dating the others. Nobara would likely act smug though Yuji might fuck up her plans being the one most likely to openly confirm their relationship (he tends to not read the air as well). Megumi would simply rebuff anyone flirting with him, even the other two.
Idk who cooks, I don’t think any of them would be great at cooking. They might make less fuck upable meals like shabu shabu or fried rice.
Nobara drinks the most and can get rowdy but holds her liquor well, Yuji moderately drinks and has to haul back someone by the end of the night, Megumi is not fond of drinking but is a lightweight so gets in the most trouble at a drinking party.
Fushiguro is the designated driver, Itadori is the pack mule, Kugisaki is the planner.
Itadori is the one who socializes with the neighbors. He concerns them at first with the hair and the scars but charms the neighborhood wives after helping with community events.
Gojo is in the butsudan alongside Yuji’s grandpa and Megumi’s sister.
The main group activity ultimately becomes watching movies.