Ah, but it gets even curiouser and curiouser. Intrigued by this discussion, I looked up the aforementioned Mr Aubone. I'd thought he might be from Louisiana, and the pronunciation might reflect Creole influence. But no, he was born in Miami and spent most of his early life in Florida. His university page, however, gave his father's name, which when I googled it, revealed that his father is in fact ... Argentinian (Guillermo "Willie" Aubone) en.wikipedia.org/wiki/Guillermo_Aubone So the rather unusual pronunciation may be an example of what happens when a patronymic goes through not one but two language shifts ... and the fault, dear SC, may lie not with the Americans but with Latin America.
And, in fact, I think the the pronunciation guide on the page that SC linked to can hardly be trusted anyway because it has Jean-Yves written as 'Jon EEs'.
Jean-Yves is obviously a bog-standard French name, ten a penny. The 'jean' is obviously not 'jon' with a hard dj' but a soft 'zj' - usually denoted by that fancy 'z' letter in phonetics.
And EEs ??? Where's the 'v', for crying out loud ????
(The 'yves' is done with a south of France accent; the Parisian version would be far shorter and more one syllable than two, but it's not wrong - and LOTS of 'v' and no 's').
Unfortunately no Aubone.
The name may originally have been 'au bone' or, indeed, 'au boné' but that doesn't really help.
So, to me, the page makes no sense - and then I went and looked on youtube and found an interview with the guy and the interviewer pronounces 'jean' correctly, has 'yves' as more like 'eevsss' and says 'aubone' as 'oh- BOH- nay' i.e. definite last 'é' but stress more on the second syllable.
And there's also lots of links to Spanish/Latin American Aubones - didn't go on them but, as you found out Spec, there's obviously a strong Latino Aubone line.