@banjomarx—
What is the Japanese term that you're translating as “late”?
Again: The younger Haku does not seem to have assumed any prerogatives or responsibilities beyond those of an heir presumptive; so, whatever the title, she doesn't seem to hold it yet.
There was a character in
Catch 22 named “Major Major Major” who was assigned the rank of major, making him Major Major Major Major. However, no single instance of “Major” therein was
both a name and a title, and he didn't lose a part of his name in the creation of the title. If “Haku” were both a name and a title, then the entitled Haku could be called “Haku Haku” or “Haku the Haku”.