Re: Ms Kate / Mr Thomas
It's still common in the South (by people of all races) to use "Miz Kate" when just "Kate" is too informal.
Also, children throughout the country may use "Miss Patty" for a caretaker or other adult. My daughter, who is about to be 14, had a wonderful, wonderful pre-school teacher when she was 4 who was called Miss Patty. To this day, whenever we see her in town, the entire family says "Look! It's Miss Patty! How are you?" even though by now we could call her either Patty or Mrs. Whatever-her-last-name-is.
My coworker refers to me at "Miss Barb" when she talks about me to her children.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.