Depending on parring slow burn enemy to lovers(Shego) or childhood/best friend to lovers(Kim) or you could do both and make it a poly it would be interesting to see what would happen if Femharry started dating Shego first🤔
Hogwarts could do the tri wizard tournament after golden trio graduate(even though femharry won't go to Hogwarts) to cut the building tension(18/19). So it's obvious that Femharry(Carmilla after the lesbian vampire Marlene got to name her because James and Lily lost a bet. Marlene is predicting the future love life of her honorary niece) is not related to Kim through her mom. No she is adopted by the Stoppables(Ron's family) who are squibs maybe or have just enough magic to use it for body reinforcements after being abandoned by the Dursleys during a business trip and found by the Stoppables. The Dursleys get arrested and Marge comes to get Dudley at the beginning of her questioning Carmilla has a bout of accidental magic so the police who have a secret Aurors department so it's easier for MACUSA to track things(crimes) like this investigate and find out who she is and are stumped on what to do with her cause no-magi law dictates it's not there jurisdiction while wizarding law states it is Carmilla who has been clinging to Ron's mom and Ron's hand (slight big bro Ron) the entire time ask if she can live with the Stoppables because they have been the only adults that have been nice to her so 1 problem solved many more to go. While Carmilla is being fostered by them after a week they get taken to Gringotts by a Aurors they do an inheritance test and find out that she is on potions and blocks surprise *jazz hands* not only do we have a good dark side but turns out Carmilla has a Magical mother bond with Bellatrix(boy was she surprised to feel that bond when Carmilla got purged) and a "wrongly imprisoned" dogfather(they both break out 3rd year) and not only is she a Metamorph but was left quite a inheritance by not only her parents but by there friend groups too, due with that as you will. Money responsible Carmilla much to Ron's chargen😭. Carmilla and Kim after meeting become attached to the hip to the point the Possible family see her as another kid. After healing Carmilla turns out to be a fairly energetic and athletic kid who can keep up with Kim. So Kim and Carmilla with Ron as a sidekick during missions. Carmilla is a magical agent of Global Justice in other words a special agent that works with MACUSA this way she can have her own villains besides thoughts she shares with Kim. She can meet Shego this way since she was hired to steal a magical artifact? Before the meteor hit the Go family they were magic it just changed how they use there magic. For Shego and Carmilla's mission/work relationship maybe they have a nobody but me can mess/fight with you or we fight constantly but I will die saving you or maybe I will always put you first type of thing(ride or die) if a Kim parring this can go a sibling/best friend route maybe the last 2 could apply to Kim also, during off hours/civilian time there dynamic could be a it never happened or what happens during missions stays in missions.