Growing up in Baltimore we (as kids) called our neighbors by Mr. or Miss and their first name (Mr. Henry, Miss Nancy, Mr. Norman, etc.). I’m told that’s a southern thing.
Currently, in Israel, I work for an Israeli company with an American client. All those who work here in Israel currently go by their first names. I give everyone the choice as to how they want to be called; one chareidi gentleman asked to be called “Mr. Lastname,” which is fine and not a problem. All of those we work with in America go by Mr. or Mrs. and their last names.