Challenge
Harry potter must become a clan chief of a Scottish clan along with another nobility title not related to the clan the title may be by right of conquest,blood adoption or any other way you can think of.
Harry must stop a feud that has been going on for more than 500 years whether by peaceful means or total destruction of that clan and all its branches.
If he destroys all this branches of the clan his clan is feuding with they must be brought to a muggle court and get off on an obscure a nearly unknown law that was passed for clan feuds.
It would be better if there were manipulative Dumbledore and weasley in this story but not necessary if that happens then a feud with clan weasley would be a required at a point in the story but you may make it as important as you want or not as the case may be.
He must have at least a wealthy amount of money but not extravagant and he should not own buildings like Windsor castle Buckingham castle or any other things in the crown estate or from the Monarchy these items may be bought later on but cannot be own via inheritance from harry potters ancestor.
The clan should have a clan castle or other such fortified meeting places if so It should be in good repair or the castle is magically repaired to a state of use incase of it needing to be used as a sancuary in times of war.
I would suggest it be on an island but that is up to you to decide if it fits in with your story.