Honorific
Yes
Mr and Mrs = Familie
Mrs. Fairfax
The proper way to address that letter would be "Mr. and Mrs. John Doe."
Mr Bean's landlady in the animated series is Mrs Wickett.
Mr and Mrs
Mrs McGrath
Formal titles.
The Honorable Judge Smith and Mr. Smith for the envelope and Judge Smith and Mr Smith for the letter.
Mr and Mrs is correct or Mrs and Mr is correct
In a letter: Dear Mr / Ms / Mrs name In speech: Mr name
Mr. and Mrs. (ex. "Hello, Mr. and Mrs. Evans" instead of "Hello, Mrs. and Mr. Evans")