Xander as the elder half brother of Harry Potter, who has had a comprehensive magical and mundane education, unbeknownst to anyone in Sunnydale barring Jesse McNally who was a First Generation Wizard.

Special Magical Talents = Shamanism, Runes, Warding, Combat Magic, Magical Craftsmanship & Enchantments, Wolf Animagus, Mind Shield, Rituals

Also has a large trust fund & a fully secure Manor house in Colorado Or Wyoming that no one has access to outside of himself.

At age 17 he graduates both from his Magical & Mundane schooling & is accepted as an Auror

When the Dursley family is killed, he gains full custody of his half brother.

Helps Harry, Remus & Sirius get a Full = Examination, Cleansing, Physical & Psychological Healing, Private Mundane & Magical Education Tutoring, Restraining Orders, Inventory & Investigation Of All Properties & Assets By Blood-Magic-Law(e.g. Lineage, Bequests, Gifts...etc),

Wizarding Britain ends up getting a comprehensive, detailed & systematic investigation in their government, education, economy, medical...etc

And when the Scooby Gang find out and try and interfere, they end up being fully investigated, cleansed, physically & psychological healed, educated on reality & trained/backed up properly in combat if they are not arrested themselves

Extras

Bill & Charlie Weasley transfers even further away from England,

Percy Weasley decides to become a ICW Lawyer instead of becoming British Ministry toady,

The Twins become R&D Scientists with a private Canadian company with their dream Joke shop as a side business,

Ron Weasley enventually becomes a Oceania Auror after his attitude is worked out of him,

> all of them have minimal contact with their overbearing banshee mother or doormat father & continually refuse to go back to England

Hermione is continuasly shown the error of her ways such as in daily-chan fanfiction,

None of the Hogwarts staff are allowed to get away scott free as they are not innocent bystanders

No Tonks/Remus relationship as she's too immature/naive for him

Both Xander & Harry get adopted into Black Family