Salutation for a current Ambassador is His or Her Excellency. Also Ambassador and last name of and country. I believe that since former military and President and Senators etc.....retain their title....Like President Carter.....and military usually has Ret. after the last name I think as a salutation on an Envelope it would be His Excellany John A. Gavin, Ret.
Dear Mrs Ambassador..
Dear Mrs. Obama,
No honorific is required when addressing the former chairman of a committee.
On the Envelope His/Her Excellency Mr./Ms./Dr./Rev. [name] Ambassador (or High Commissioner) of [country in full] In letter Dear Mr/Mrs Ambassador
"Your Honor" or "Mr. (Mrs.) Mayor"
The salutation for a former judge is typically "Judge [Last Name]" if you are addressing them formally.
His Excellency, Ambassador of ................... This salutation can be used when writing to the Forein ambassadors of all countries.
The proper title for a retired ambassador is "Ambassador (Ret.)"
An ex-ambassador is often referred to as a former ambassador or a retired ambassador.
The proper salutation for a probate judge is "The Honorable [Judge's Full Name]."
What is the proper salutation for a register of wills, e.g. Honorable John White?
Many people will call him Senator as a mark of respect. In writing he could be referred to the Honorable xxxx or former Senator xxxx.