Not necessarily. It could be a blend of truth and imagination. Maybe there's a kernel of a real story, but it's been embellished and fictionalized to make it more engaging.
It might be. Many stories are based on true events with some fictional elements added for dramatic effect. For this one, you'd have to research the source to be sure.
One common element is the sense of panic. People in a burning house are usually terrified. Another is the destruction of property. The fire often causes significant damage to the building and everything inside. And there is usually a call for help, either by the people in the house or by neighbors who notice the fire.
Well, in a 'house on fire true story', often there are stories of survival. For example, some people might find a way to hide in a safe part of the house until the firefighters arrive. There may be accounts of how quickly the fire spread and what kind of damage it caused to the property. Maybe the family lost all their belongings but were just glad to be alive. And it could also be about how the community came together to support the family after such a tragic event.