I doubt it, I've certainly never heard or seen it used. If you are writing to a married couple then "Dear John and Mary" (for example) or more formally "Dear Mr and Mrs" are the usual forms of address. For other pairs of people their first name or more formally their surnames would be correct. For example "Dear Martin and Simon," or "Dear Mr Smith and Mr Hughes."
Traditionally, a colon for business letters and a comma for personal letters.
EdD indicates a doctorate degree. Proper salutaion would be "Dear Doctor xxxxx:"
Dear Mr.Donahuue,
The correct and most used and common one is Dear
The phrase "dear gentlemen" is grammatically correct, but it may sound a bit formal and old-fashioned. It is more common to address a group of people as "gentlemen" or "dear friends" instead.
The correct female title is ' Dear Madam, '
it depends if you are writing a complaint it would be the title with out dear and if a friendly letter dear is correct
Dear ms
yes
The homograph for "dear" is "dear." It can mean both loved or cherished, or expensive or high in price.
Dear Ms. Holly preferable to add a last name if possible.
Dear Father, Dear Reverend Father or Most Reverend Father