It does seem that they were in their own way made Tranquil with the loss of the Titan, but still able to function with emotions unlike actual Tranquil who need a spirit to break it.
I am beginning to think his anger if you drink from the Well stems from what he saw of Mythal's treatment of others. She may have been the best of them all, but she was still abusive when needed. I can't help but feel he was indirectly involved in her demise and that's also why he torments himself over her death.
Speaking of lyrium and dreams, what's this mean you think?
WE ARE HERE
WE HAVE WAITED
WE HAVE SLEPT
WE ARE SUNDERED
WE ARE CRIPPLED
WE ARE POLLUTED
WE ENDURE WE WAIT
WE HAVE FOUND THE DREAMS AGAIN
WE WILL AWAKEN
I used to believe that this codex referred to the Creators, that we now know are called the Evanuris, because they are known to be imprisoned possibly asleep. Though the sundered, crippled and polluted parts didn't make any sense unless they were tainted (and they might be!).
It makes tons more sense for the codex to be referring to the Titans, who were literally sundered by the Evanuris to harvest lyrium, and "something else" - probably their hearts (which may actually be what the Evanuris' orbs were made out of). They were sundered, crippled, and polluted - TAINTED, somehow, which is why there is red lyrium for them to speak through.
They seem to have been asleep for a long time, possibly because of the Veil, but it seems they have found the dreams again. The only thing I can think that means is that they have found a way to reconnect with the Fade, even with the Veil present, or they are directing/assisting, assisted by the force that will cause it to be destroyed.
The rumblings in Descent and the powers that Valta gained may be just the beginning for the dwarves and their society recovering, or being reborn - which may prove disastrous for anyone living on the surface. Especially, since it seems at least a few of the Titans (or their corpses) are contaminated by red lyrium. Healthy Titans seem to resist or repel darkspawn, so perhaps they have a resistance, or they have yet to be tainted.