yes
"To the Smith Family"
In a salutation, the word "family" is not typically capitalized unless it is being used as part of a proper noun or title, such as "The Smith Family." In general usage, it is lowercase, as in "Dear Smith family." Capitalization rules in salutations are based on standard grammar conventions and style guides.
The salutation for a retired General is "General". A retired general can also be addressed in a letter thus: General W. Smith (ret):
The Honorable Judge Smith and Mr. Smith for the envelope and Judge Smith and Mr Smith for the letter.
Dear Mr. John and Rev. Sally Smith,
Dr. and Mr. Smith.
"Dr and Mrs Smith" is the correct salutation. (With Smith replaced with the correct surname)
You could address it to Reverend and Reverend Smith. The alternative would be the Reverends Smith.
Depends on whether you wish to be kind, or offensive, right?
Dear Judge Smith and Mr. Smith.
Dr. and Mrs. Smith
Dr. and Mr. Smith.