So, as I was looking at the covers for Kakashi Hiden and Shikamaru Hiden, I noticed something interesting...
Naruto: Tales of a Gutsy Ninja, Naruto: Blood Prison, Naruto Jinraiden: The Wolf that Howled at the Sun, and the new Naruto Hiden series all have the same basic book cover layout. The other novels (film novelizations, for the most part) don't follow suit. Also unique? These books all feature illustrations by Kishimoto Masashi.
Cover comparison: http://i.imgur.com/ljP4pne.jpg
I also noticed that the novel version of Blood Prison technically doesn't have the same title as the film version, unlike the novelizations. The film is Naruto the Movie: Blood Prison (劇場版 NARUTO―ナルト― ブラッド・プリズン, Gekijōban Naruto: Buraddo Purizun), while the novel is titled Naruto: Blood Prison (NARUTO―ナルト― 鬼燈の城, Naruto: Buraddo Purizun). Which is interesting, because the author of the novel actually wrote the original screenplay for the film...
So, anyway, I bring this up mostly because Kakashi Hiden references the plot of Blood Prison, but seemed to change details. I can't help but wonder if the novel version is different from the movie version, and if that might be where some of the changes come from?
I also wonder if these books all share the same level of canon, given the obvious similarities (beyond most of them being written by Higashiyama).