Not in the US. Using Mr. or Mrs. with a first name only (like Mr. Fred or Ms. Judy) was originally the way slaves were instructed to speak to their masters as a way of showing deference. Today, it is practiced only in the South as a lingering remnant of racist practices. It is appropriate to address someone named "Fred Jones" as Fred if you know him, Mr. Jones in a business setting, or Mr. Fred Jones in a more formal or traditional setting. Addressing him as Mr. Fred is considered derogatory and disrespectful.
Yes
The Mouses. Since Mr and Mrs Mouse are proper names, they would not be contracted to a different spelling in the plural.
Assuming a business letter to husband and wife with different last names who you don't know the proper business salutation is to have the the wife's name first before the husband's accompanied by the proper titles. For example: Dear Mrs. Thompson and Mr. Jones, (salutation on letter) Mrs. Susan Thompson and Mr. Jeremy Jones (address on envelope and letter) Note that you could use "Ms." instead of "Mrs." if you prefer, although I recommend that since in this example you know they are married I would choose "Mrs." Jim Lumley jimlumley@live.com
is is correct to use Dr. Mrs. for a female doctor?
It depends on how formal you want to be. The most formal and sometime offensive to the bride is, Mr. and Mrs. (MALE FIRST NAME) (MALE LAST NAME). Example: Mr. and Mrs. John Doe Informal, just use the last name (LAST NAME)s or use both names (MALE FIRST NAME) and (FEMALE FIRST NAME) (LAST NAME) example: John and Mary Doe If the woman has chosen to keep her maiden name you should to use both last names. So it depends on how formal you want to be and the preferences of the couple on how they prefer to be addressed.
What kind of couple? Unmarried? Their names, So and so, and so and so. Married, Mr. & Mrs., any way you want to write it. Or, Mr. and Ms.
Chicken
Johnson is a proper noun, the surname of a person; mister is a common noun, a word for a male person. In the use, Mr. Johnson (abbreviated title), the noun Mister (Mr.) is used as a title for a specific person, a proper noun. Together they are a proper noun.
There isn't enough information provided to determine the first names of Mr. and Mrs. Franks. It would depend on the specific individuals being referred to.
The Honorable and Mrs. (first name with middle initial, if any) Smith
Mr. John Doe and Ms. Mary Smith
not there haha