From what I recall, the plotline of B'Ellana and Miral "dying" was set up in ASD (one of the "report" sections).
That plot development was created by Kirsten for Full Circle
, and Keith just inserted a subtle tease for it in ASD. It doesn't make sense to refer to that tiny little throwaway Easter egg in Keith's book as the "start" of Kirsten's series.
As for TTN and TNG, IIRC they referenced the Voyager/Full Circle fleet (TTN - your very own Over a Torrent Sea) and the TP (the end / epilogue of Losing the Peace?)
All of us doing the first wave of post-Destiny
books coordinated our efforts for consistency and inserted passing nods to each other's books as appropriate. I believe I was specifically asked by Marco Palmieri to insert a line or two acknowledging the emergence of the Pact. But a passing nod is not a crossover. And I still don't recall anything in ASD that specifically referenced Titan