Does Tuvok (in the latest Titan
novels) know Janeway returned?
Well, naturally it hasn't been addressed, since at least two of the TTN novels set after that event were written before this novel was, and the latest was coming out before it and thus wouldn't have spoiled it. But I don't think there's any reference in those novels to Janeway not
being alive. There's also a yearlong gap between Synthesis
and Seize the Fire
, so there would've been plenty of room for Tuvok to receive and deal with the news "off-camera" between installments.