As mentioned in another thread, Thomas Riker also shows up in in one of the Slings and Arrows eBooks, which were set in the lead up to First Contact.
Not exactly. Tom is discussed in "A Weary Life", but he doesn't actually appear in the story.
Personally, I prefer to think that Tom was recaptured after Imzadi II, then rescued by the Defiant in "Promises Made" It's not so much that I'm deadset against the character being killed off, if it was done well in a moving story. But to just mention in passing, "oh yeah, that guy totally died..."?