The question focuses on how we should structure expressions with a form of address, such as Mr., Frau, etc., or a title, such as Dr., Prof., etc., and a proper name, such as Smith, Yamada, etc. In order NOT to open the door to confusing this issue with the problem of the structure of proper names, I want to restrict the discussion to a form of address and/or a title and one proper name.
Please note that German, for instance, can have all three items present, and then the order is clear: form of address+title+proper name.
a. Guten Morgen, Herr Doktor Müller!
Titles and forms of addresses are free expressions in English, German, French, and many other languages. They can appear without proper names:
b. The prof’s not in yet. c. Careful, mister! d. Wünschen der Herr noch etwas? e. Bon jour, mademoiselle!
I believe it is therefore safe to assume that forms of address and titles must be in a syntactic relationship with the co-occurring proper names within the greater NP. The problem concerns syntax.
The question then is: How are expressions structured? May we assume endocentric structure? If yes, what’s the head? Is it (f) or (g)? Why? Or are we dealing with exocentric NPs? If so, why?
f. [Mr. [Smith]] g. [[Mr.] Smith]
On a final note, there are languages, such as Japanese, where the form of address is a suffix (h). If titles are present, one often deals with compounds (i), at least in Japanese.
h. Yamada-san "Mr/Mrs/Miss Yamada" i. Yamada-saibankan "Judge Yamada"
Languages that use affixes and compounding, such as Japanese, may offer a hint concerning the internal structure of the expressions in other languages. In Japanese the head is always at the right periphery of its phrase. This property is also in effect in morphology. If true, -san in (h), and saibankan in (i) should be the heads.
But would the corresponding expressions also be heads in languages that use free expressions?