Harry Potter gang being placed in different houses (while of course still being the most lovely of friends)
Like Harry can still be Gryffindor, but Hermione be in Ravenclaw, and Ron take his rightful place as the ULTIMATE HUFFLEPUFF.
And dunno maybe Draco is dissuaded from his awful upbringing (and self serving drarry reasons) and joins the group as their Slytherin because he needs love and affection (and drarry) and to be shown he is cared for by peOPLE.
Main motivation for all this is transparency of houses like the Hogwarts layout would be opened up to showcase the inner workings of all houses functioning/shenanigans?
Everyone coming up with ridiculous call signs to summon each other after infiltrating their common rooms (with poor stealth skills of course)
Harry Ron and Draco up at night sneaking around trying to get into Ravenclaw so she can be a part of the (put title adventure here) but they can’t figure out the stupid riddle so Ron and Harry are just whisper-screaming gibberish/the names of candy at the eagle because hey that usually works at Hogwarts while Draco just punches the door repeatedly until Hermione whose already outside calls out the answer from behind them because she totally figured out the mystery five minuets ago but there’re bound to be more cause this school is trying to kill them
Ron and Harry aggressively (but playfully) being all competitive over Quidditch matches chanting at each other in full house attire
Ron purposefully teaching everyone the wrong knock for Hufflepuff’s room so they’re doused by vinegar.
Draco literally hissing at being exposed to the overwhelming amount of yellow and brightness and overall pEPPY HUFFLEPUFF INTENSITY until Ron hands over some sunglasses that everyone in Hufflepuff just happens to have on standby saying “you get used to it after a few years,,,sometimes.”
Draco acting as a double agent acting to continue his mission in Half-Blood prince but is aided by Harry because “VOLEDEMORT IS IN MY HOME HARRY WHAT THE FUCK AM I SPOSE TO DO WITH THAT” so he helps a disguised Harry sneak into Slytherin to investigate and spy on which classmates Draco knows are interested in becoming Death Eaters to try and find a link, but Harry of course is all Gryffindor and keeps screwing with everything in the common room much to Draco’s dismay because first and foremost he’s “still a Slytherin bruh could you like not. C’mon I’m breaking a seven centuries “No Outsider Has Ever Been In Here” rule—be nice to the squid don’t taunt the squid the squid did nothing to you we live in a dungeon don’t make this any worse—OH MY MERLIN NO DON’T CHANGE THE LIGHTS FROM GREEN TO YELLOW HARRY IT’S LIKE A SUN (dissolves into hissing fit) we aRE tryING TO Be DiSCreT”
Draco being harassed by some of the Death Eater Slytherins and despite his housemate friends trying to defend him it’s still a lot to deal with especially exposed during sleep so Harry Hermione and Ron all work together to hide him in their house rooms on alternating nights (using magic okay just some magic) until someone discovers him in the Gryffindor common room and get like super Gryffindor vs. Slytherin antagonistic about him being there but before they can kick him out Harry’s ‘nah-uh’ and stands in front of Draco protectively explaining how he’s helping Hogwarts as a whole and honestly “why should we be so uptight about house entrances? Let’s not separate alliances by where we’re from we’re all fighting for the same reasons here” and the Gryffindor’s agree to let Draco stay with them due to the circumstances
but after all that the house communities become more free flowing as the war approaches with people of differing houses being allowed into common rooms to discuss plans and precautions, more people being comfortable sitting at any table in the great hall, rivalries being more like friendly competition than angry battles about which house is the most important
the first time the sorting hat calls out “SLYTHERPUFF”
everyone genuinely applauding whoever wins the house cup
Mixed house slumber parties