In response to your Janeway question in the spoiler section:
The book was Before Dishonor. The short version is, she went out to investigate the cube that Picard effectively neutralized in Resistance. That cube evolved, assimilated her, made her its new queen and was ultimately destroyed.
And yes, Sisko came back as of Unity and has been present in the DS9 relaunch books since then....Worlds of DS9 Bajor (maybe some others too, I can't remember), Warpath and Fearful Symmetry.