[@MrDidact] I can have it as his son is now the Lord of Three Corners. The mom as acting regent. Or something to that affect. 

Could you expand upon the meaning of High House's mingling with a House one step above commoners?

As for bastards of Great Houses, only one has proof they are, all the rest are just story's and unfounded claims. Whether they are, or are not, is ultimately up to the progression of the story, and your final say of course.