Yes, the plural for Smith is Smiths, and the plural possessive is Smiths'.Do not forget to capitalize names; names are proper nouns.
dear Sirs:
The plural possessive form of "smith" is "smiths'".
Dear Mr./Dear Ms. followed by their surname.
EdD indicates a doctorate degree. Proper salutaion would be "Dear Doctor xxxxx:"
Dear Principal, or To Whom It May Concern, or Dear Sir or Madam
John and the Smiths took my mother on a picnic in the park.common nouns: mother, picnic, and park.proper nouns: John, and Smiths.
Dear Mr. Smith and Mr. Jones or Dear Sirs as an example
"Dear Mr. Johnson" 'Dear Ms. Johnson" Dear Mrs. Johnson" any one of these will do just put in their proper name.
Dear Counselors:
Yes, dear is usually at the start of a sentence and beginning of the letter. If it is not, then it needs no capitalization.-------------------It is OK, but do not use "Dear Employer." Find the name of the person to whom you are sending the letter. It's polite and more friendly.
Dear Madam (but sign it Yours Faithfully) or Dear Miss..... (sign Yours sincerely) or Dear Mrs..... (sign Yours sincerely)