Idea 10 HP x Btvs (Buffy the Vampire Slayer)

Hogwarts does the tournament in 7th year. The summer of 2rd year the watcher council/unspeakables get a large magic spike that is Ophelia(Fem!harry or twin of harry)/and Harry coming into a early creature inheritance(something protective) the watcher council gets there first to find a unconscious and clearly abused 13 year old little girl/and boy is the cause a squib that was on the investigation team recognizes her/them so they decide to take her/them. She/they are put under the care of Rupert Guiles he is not happy at first and she/they don't trust him despite her/their creature instinct saying they can cause he is an adult and adults have done nothing but hurt and ignore/not help her/them, but after half a year he comes to adopt her/them they don't go back to Hogwarts after the summer but get foci tutors and learn nature? magic. When Giles goes to Sunnydale California to mentor Buffy she/they follow and find out Ophelia is the Slayers protector/soulmate(only applies to Buffy unless doing a poly with Faith could all so do Drucilla as a soulmate)/ and Harry is soulmates with Xander Harris and or Angel who was interested in Buffy till then. While I would like you to do all seasons of btvs you don't have to but an idea for the Halloween episode maybe Ophelia could go as Wonder Women and ends up keeping her powers and items or you could do couple/best friend incase of slowburn costumes of Harley Quinn (Buffy) and Poison Ivy (Ophelia) Xander got Ophelia/and Harry addicted to comics for Harry if you add him maybe John Constantine? Can not do superman to op for the crossover verse