A letter would be addressed to Mr. and Doctor. If they are both Doctors it would be Doctor and Doctor.
Dr. and Mr. Smith.
Dr. and Mr. Smith
vmrs
probabaly just a mrs. would suffise
Hello.
addressing attorney and wife
It would be Doctor and Mrs John Doe in most situations. If she was the Doctor it could be Mr and Doctor John Doe, but that is a bit presumptuous to use his name with her title.
Rabbi and Mrs.
Dear Mrs Ambassador..
"Dr and Mrs Smith" is the correct salutation. (With Smith replaced with the correct surname)
Dear Judge Smith and Mr. Smith.
Mr. James Brown & Dr. Angel Brown