idk why no ones done this yet but please consider: ghoul itadori yuuji.
its like an ichigo type situation, a little? jin and wasuke are ghouls, and wasuke knows that something about kaori is weird bc she smells funny, and neither jin nor wasuke expected kaori to be able to have yuuji. jin is delighted and wasuke is suspicious.
kenjaku has no idea that jin is a ghoul. yuuji, as a ghoul-baby, needs flesh, and so hes constantly eating kaori from the inside out, forcing kenjaku to constantly use RCT so as not to pass out. kenjaku-kaori has never been the one carrying the baby before so they think this is completely normal.
when kaori tries to seal one of sukuna's fingers in baby-yuuji, he just digests it.
so here we have yuuji: 1/3 human, 1/3 curse, 1/3 ghoul.
his funky genetics lead to some fun features!! some of them only develop after kaori and jin are out of the picture and wasuke is stuck raising his beloved mutant baby.
yuuji's eyes are a bright yellow gold colour, and he never develops kakugan, but he does have tapetum lucidum, which makes his eyes reflective. he also has two auxillary eyes beneath the main pair that widen his feild of view and can percieve cursed energy.
he has a pink coloured bikaku kagune, which looks like a mix between a pangolin and a kangaroo tail; he can use it as a chair, a battering ram, a bat, etc.
he can eat human food, but it takes a lot to fuel him, so he still has to eat flesh; interestingly he also has to eat curses, which dont taste good or bad, but are just a lot. theres so much flavour in them that it makes him flavour blind for hours after.
anyway, he meets and befriends geto at age 5 when he travels thru sendai on a mission and yuuji sees him eat a curse and immediately just goes "FRIEND"
so suguru forcibly recieves discout therapy from a child with a curse technique thats so similar to his own that hes getting flashbacks to his own childhood, and he starts training yuuji in secret bc he cant just abandon this kid!!
so wjen he finds mimiko and nanako he kills one (1) guy and brings them to wasuke, grabbing him by the pant leg and just going "PLEASE PLEASE PLEASE PLEASE PLEASE" and wasuke cant say no so hes just like "fine, i guess"
eventually, well after gojo takes in tsumiki and megumi, suguru is forced to introduce his kids to satoru's kids after he meets them for the first time when the kids are like 13. why?
tsumiki is a full ghoul, and megumi is a half ghoul, and he can smell yuuji on suguru.
so toji was completely human, but his wife was a ghoul! megumi survived bc his cursed energy fought his mom while she was carrying him. megumi's eyes stay green when his kakugan activates, but he's actually 2/3s human, so he lacks the full strength, stamina, or speed of a ghoul, but he does have a stupidly fast recovery/regeneration, and an incomplete koukaku kagune that act like porcupine quills defensively on his back. they rattle when hes upset or flustered!
tsumiki has a rinkaku kagune that look like mantis arms, like their mom.
now canon happens before they get a chance to meet, except sukuna doesnt incarnate bc yuuji just eats him whole, soul and all, and so when gojo appears and looks at yuuji's soul he has to do a double take cause what the fuck is up with this random kids soul??
and then megumi just picks him up and is like, "okay are we going" and gojo asks him why hes taking the kid with him and megumi is just like "he's mine now, hes joining our class"
anyway the story goes on as normal with kenjaku quietly screaming at all their plans falling apart for some reason they CANT IDENTIFY??? and also soft satosugu reconcilliation and getting together facillitated by their kids.
gojo is bullshitting his way thru older siblinghood, constantly gaslighting the higherups about his kid's eating habits and convincing everyone that his class is a set of three perfectly normal completely human 15 year olds.
yaga doesnt believe him, but he has panda so he cant judge.
shoko is very happy that two of the three kids dont need her RCT, but also exasperated that two of the three kids need her morgue.
utahime keeps trying and failing to prove that satoru's kids arent human and its getting to the point where shes actually failing so hard that shes convincing people otherwise.
nanami is absolutely certain these kids arent human (including nobara), but hes not paid to do anything about it so he doesnt care.