No, it isn't. The Canterbury Tales is more like a anthology of separate tales. It showcases a wide range of characters and their narratives, rather than following the typical structure of a novel.
In the 'Canterbury Tales Graphic Novels', there may be some simplification of the language compared to the original. Since they are aiming at a potentially wider audience, including those who may not be well - versed in archaic English. Also, the graphic novels might emphasize certain aspects more through the visuals. For example, if a character has a particular vice or virtue, it can be highlighted in the illustrations more prominently than in the original text where it might be more subtly described.
Definitely fiction. The Canterbury Tales presents imaginative and often humorous narratives that are crafted by the author's creativity rather than being based on real events or people.
The Canterbury Tales is an interesting mix. It's not purely a poem or a novel. It's a compilation of stories told by different characters in various styles.