I read "The Fourth Toast" from SNW3 as well as the relevant sections of "Vulcan's Heart".
"Fourth Toast" was a decent enough short story, though I found it difficult to swallow that Castillo and Parker's escape pod made it past the Romulans, who would not have found it in their interests to allow survivors to get away.
I saw no mention in VH of the final outcome for the survivors beyond Tasha's arrangement with Volskiar so that seems to leave their fates unknown; furthermore, Yar's death (or "death", if you subscribe to the theory that her usefulness to interrogators outweighed her usefulness to Volskiar in raising Sela...) certainly alters the deal. But since Yar clearly never found an opportunity to get word to the Federation about them, from the Federation's point-of-view all hands went down with the C at Narendra 3.
Although I haven't gotten around to reading many of them yet, I am surprised that discussion of the Ent-C survivors hasn't been made in any of the books taking place during the break in the Romulan Star Empire. It seems (to me, anyway...) that if those folks are indeed alive or their fates are otherwise known by some moderate Romulans who view the Federation as more friend than foe (such as Donatra, while alive), it would be...interesting. Or does the existence of poorly-written fanfic prevent you authors from delving into that possibility? Rescue mission into Romulan space; yeah, farfetched. Political intrigue regarding Starfleet personnel held prisoner for decades; more plausible.