In my Dark Urge replay, I'm resting more, and still haven't gotten Astarion to admit he was a vampire - probably due to not being far enough along in the story, or maybe my influence is too low.
It was great to visit the tea house and see him lie to the player about being a vampire. He says Cazador is a slaver. Astarion will say the gur lied if the gur says he's hunting a vampire spawn named Astarion too. There's also the wild bore that you find that's been drained of blood.
In my game, Astarion admitted to me that he's a vampire in a conversation in camp.
Then after couple more hours, when I encountered the hunter and talked to him about it, he denied being a vamp and said the hunter lied, acting as if the previous conversation never happened.
Then he tried to bite me at night, and my character acted like it's complete news to him that Astarion is a vampire.
This is the kind of reactivity I expect from a $60 RPG. Amazin