It's hard to say. You'd have to investigate the context and the author's intentions. Maybe there are elements of truth mixed with imagination to create the story of Kate Wallis.
Yes, it is. There are real - life events that inspired stories related to Kate Mara as a teacher. However, without more specific details, it's hard to elaborate fully.
I'm not sure specifically which 'Kate Kensington' you're referring to. There could be many people named Kate Kensington. It could be a local story, a family story, or something related to a particular community or event. Without more context, it's difficult to tell the true story.