specifically Mycroft.
I always saw Mycroft as a Slytherin, cunning and clever and ambitious with a definite level of coldness (The Ice Man.) But he’d be one of the more polite/nicer examples of a Slytherin who always did well in class and was diligent ad the teachers liked him. Many people would have expected him to be in Ravenclaw. He would have been a Prefect/Head Boy and probably interned at the Ministry of Magic.
Then to everyone’s surprise he left to live in the Muggle world and wen’t into politics. Why? because the Minister himself can’t talk to the Muggle leaders about every little incident where the Wizarding world intrudes a bit. So Mycroft is there to tidy things up and keep relations, however secret they may be, friendly.
But this mainly negotiation filled position of course cover’s up Mycroft’s real influence. Not many Wizards are so adapt with Muggle technology and social conventions as him. Many Wizarding folk mistake him for a Muggle at first glance.
Also his Umbrella hides his wand in a manner more similar to Lucius Malfoy’s snake cane than Hagrid’s Umbrella.
Also the giant chess pieces in his house are Wizard’s chess pieces like in McGonagall’s defence for the philosopher’s stone