I don't doubt that some survivors of Titus' group would have moved into the Venatori, but it would have been nice to have this acknowledged in-game, by someone like Eremond. There was also nothing in any codex or letter referring to the Crimson Acolytes and their plot. If you compare that lack of follow-up to that gifted the novels (Asunder and Masked Empire), it is remarkable how the events of the Silent Grove trilogy pass almost without notice, especially as Aurelian's plan was world-changing.
The Silent Grove trilogy was written around certain overrated character that can be dead, many of the characters he met are pretty relevant to Thedas and since he's the reason of most of them dying, writers would have to think about what is going on with them if they are alive, Gaider said the events wouldn't happen if your canon didn't permitted it, of course, they can disregard his word at any time, but then they would have to seek a plausible way to kill them and drop things on straight line again, since betrayal was the only reason for one of such characters dying, and a character that can have run away and wouldn't have a reason to go to Antiva without Alistair is the reason of another of them dying, they would have to scratch their minds badly to find an excuse that doesn't sound pathetic,
Like with Golems, Rock Wraiths and Werewolves, I think they thought that avoid the matter was the best answer for the plot this time, however, since DA4 will take place in the north, I don't think they can avoid this plotline any longer.