I seem to remember reading that one refers to the deceased as “the late” only for the first year after the death, as after a year it is presumed to be generally know that he or she is dead.
And GHWBush is properly referred to as “Ambassador Bush” as it is the most recent “sticky” title that he held.
I’ve never heard of this rule that governorships and ambassadorships are somehow specially sticky unlike other titles. As I said, my understanding that you refer to the person by the highest non-unique title. I might be wrong though, so if you have more details, please let me know.
It’s never improper to address or refer to someone as Mr./Ms./Mrs., regardless of any other title or honor he or she might hold or be entitled to.
I think you might get a few askance looks were you to address, say, the Queen of England as “Mrs Mountbatten” as opposed to “Your Majesty.”
Try telling that to a Senator.
What about J.C.? 
Especially since she declared that she was keeping her maiden name of “Windsor.”
I’ve never heard of it being the monk’s choice; it’s usually viewed as the monk’s first act of obedience.
And some of the names of some of the older nuns and monks do suggest it was not their choice… but I would not put it past varying with the order in post-Vat-II Roman Catholicism as a “liberalizing” move.
Back to the OP – yes, as mentioned before: “John Paul” is not a casual personal name; his family and his homies from wartime Krakow may refer to him as Karol, because that is the name of the man they know and love; to the folks he has dealt with and worked with for the last quarter-century he’s “Your Holiness” or “Holy Father”, the title of the office to whom they are loyal and committed; and heck, before that in a professional setting he was “Your Eminence” or “Your Excellency”.
Damn uppity queen, not taking her husband’s made up fake last name…
And deciding to keep her own made up fake last name.
Of course, by those standards, an awful lot of us have made up fake last names. Consider all the made up fake last names adopted by American immigrants and whole nations of people whose cultures didn’t traditionally use family names, such as Arabs, south Indians, etc.
On a nit-picking note, I’ve read that people entering Catholic orders don’t choose a name; the official term is that they have a name imposed upon them. In the case of a Pope, being as he is the highest authority in the church, he imposes a name upon himself.
On a seperate note, has the Prince of Wales given any indication on what name he will use when he becomes King? Charles III? George VII? Phil Numero Uno?
IIRC, he has indicated that when he becomes king he will like to be referred to as George VII as the name Charles has unpleasant connotations of the executed Charles I and the womaniser Charles II. However, he will be at liberty to select any one of his other given names as his regal name so can become king Philip II or even king Arthur should he so wish (his given name being Charles Philip Arthur George Mountbatten-Windsor).
If he chose Philip he wouldn’t be Philip II. Mary I’s husband was only king-consort and royal consorts aren’t included in the numbering scheme.
No, her decision was that her heirs would continue to be the House (=Dynasty) of Windsor, i.e., that Philip’s being the father, grandfather, etc., of the next monarchs would not lead to a change of dynastic name, as happened due to Prince Albert after Victoria’s reign.
As a wife, she’s Mrs. Philip Mountbatten, that being the family name he adopted. Thanks to the respect she has and the courtesy owed her as Queen and monarch, her status as Philip’s wife rarely comes into play in terms of nomenclature, but she has a couple of times acknowledged that.
In any case, Philip’s House, in the what-if scenario where the Letters Patent continuing the House of Windsor had not been issued, would not be Mountbatten, which is the surname he adopted to acknowledge his maternal grandfather and uncle, both celebrated British war leaders (who had anglicized the name from Battenberg, itself a “Fitzroy” type adopted name), but rather his father’s descent from the royal house of Greece, which in one of the oddities of 19th Century dynastic foofaraw turns out to be the Danish royal house, Schleswig-Holstein-Sonderburg-Glucksburg.
And *you we shall call ‘Brother Flounder’.
This brings to mind a cartoon I saw, of the President being briefed by his protocol advisor:
