Dear Madam (but sign it Yours Faithfully) or Dear Miss..... (sign Yours sincerely) or Dear Mrs..... (sign Yours sincerely)
Mr for males and Miss, Ms or Mrs for a female.
The proper salutation in English for either a medical doctor or the holder of a Ph.D. is the same for either male or female. It is simply "Doctor".
To whom it may concern
Rabbi and Mrs.
Dear Counselors:
A proper salutation for greeting the president of a business is "Dear Mr. President". To conclude a letter, the proper word is "Sincerely" and a the name of the writer.
Dear Mrs Ambassador..
vmrs
"Dear" is what people use it nowadays.
yes
The proper salutation for a letter to someone with an MDiv degree would be "Reverend" if they are ordained as a minister. If they are not ordained, you can address them as "Mr." or "Ms." followed by their last name.
In English, the salutation for a doctor, whether they are a medical doctor or the holder of a Ph.D. is the same for both male and female. It is Doctor.