As for the Trek series running independently from each other, that may be the case, but when looking at the TP novels, it seems to me that the story threads involve the TNG, Aventine and DS9 casts and intertwine them, so it makes sense to me as a *multi-threaded arc* (not a single narrative).
As I said, that was a later revision of the plan. Our expectation when we did the "Cleaning Up" was that the series would be going back to their independent status once again. And the original set of Typhon Pact
books was not supposed to change that too much -- aside from the lack of individual series titles on the covers, it was meant to be like the very loose crossovers of earlier years where you could read the books independently as standalone adventures in their own respective series and didn't need to read them all as a group. Clearly, the recent duology has introduced a further revision to that strategy by taking the threads from several of those standalone tales and unifying them into a more cohesive narrative arc.
Not so in with Voyager and Titan, which are telling stories Light Years apart - both "geographically" and thematically.
In principle, yes, although now the TTN books seem to have been pulled more closely into the connected continuity, which is a change from the previous intention to return them to their standalone state. Seize the Fire
and the upcoming book in the series are basically still about the ship exploring new worlds on the frontier, but with more ties to the overall political threads back home. VGR, though, is still managing to do its own independent thing and is even still a couple of years behind the surprisingly accelerated timeframe of the other post-Destiny