Earlier quoted context omitted.
You’re talking about literally billions of people, not “occasional edge cases”.
How do you figure that? Billions of people would mean over 10% of the world population having exceptional names, which seems very implausible.
From the global point of view the exceptional case is the American one, Name Middle Family. It's about 330 M people vs 8 billions, 4%, which is less than 10%.
But then you add the exceptional cases for every country or culture. From the other comments we already know that even in Western Europe there are many differences. So if you sum all those exceptional cases you get the 100% of the world population.
Edit: 330 M, typo was 353 M.