Definitely fiction. Downton Abbey creates a fictional world with made-up characters and events, although it may draw inspiration from historical periods and social contexts.
Fiction. While it draws on historical context, a lot of the specific storylines and characters are fictional. The relationships between the Crawley family members and the servants are often dramatized for entertainment. The individual dramas, like the love affairs and family feuds, are mostly made up to create an engaging plot. For instance, not every aristocratic family had the same kind of family secrets and romances as the Crawleys in the show.
Yes, Downton Abbey is based on a novel. The TV series takes inspiration from various literary works related to the period and social settings it portrays.
Yes, there are. These novels delve deeper into the lives of the characters and offer new plotlines and adventures. They're a great read for fans of the Downton Abbey universe.