Well, one notable storyline was when the War Doctor had to confront his own moral dilemma about the extreme measures needed to stop the Time War. Another was his interactions with other Time Lords and their differing views on the war's conduct.
Obviously, the new doctor is one of the main characters. There might also be patients who are central to the story, as their cases could be what drives the new doctor's actions and the overall plot. And perhaps there are some colleagues or superiors who interact with the new doctor, either supporting or opposing them.
There are also often other Time Lords and various alien species involved. The Time Lords play an important role as they are at the center of the Time War. Some of the alien species are either the enemies in the war or the victims caught in the crossfire. Their interactions with the War Doctor add depth to the stories. For instance, there might be a species that the War Doctor tries to protect from the Time War's destruction, which shows his compassionate side even in the midst of all the chaos.
It ties in with the series by building on existing storylines and adding more depth to the 'Doctor Who' universe. It might introduce new elements or offer alternate perspectives on familiar events.
Both 'dr' and 'doctor' can be used in a novel. 'Dr' is more of an abbreviation and is often used in a more informal or quick way of referring to a doctor character. For example, 'Dr. Smith entered the room.' gives a concise way to introduce the character. However, 'doctor' can be used for a more formal or when you want to emphasize the title in a full form, like 'The doctor examined the patient carefully, his white coat flapping as he moved.'
It depends on the context and the style you want to maintain. 'Dr' is more common in a formal or medical setting, while 'doctor' might be used for a more conversational or descriptive tone.
Maybe there are some military commanders in the stories as well. They can influence the situation of the war doctors, for example, in terms of providing resources or making decisions about the location of the medical facilities. Their actions can either help or hinder the work of the war doctors.