^ I don't recall the novelization of "Endgame" having anything additional. The novelization of "What You Leave Behind" has an additional battle, this one in orbit of Cardassia, and a scene where Sisko, Martok and Admiral Ross watch Jem'Hadar ships enter the wormhole.
"Endgame" expanded the Chakotay-Seven story that was started on screen with the picnic, future Janeway visiting Chakotay's grave and her later conversation with present Janeway about Seven's death.
You may be right, although the scene with Janeway dancing on Chakotay's grave is in the episode: http://voy.trekcore.com/gallery/albums/7x25-26/endgame_0138.jpg
I did say that it was in the episode. But in the episode itself that was one of only three times where the Chakotay-Seven thread was explored, whereas in the novel Carey actually gave us more on that thread.