All of them are clearly flawed in some particular ways, which in general is something good for story telling and RP wise but makes them untrustworthy of course.
Now in Chapter One we can be pretty sure that:
-If Vlaakith tells Lae'Zel to kill us, she will try. -If Shar suggest Shadowheart that we are his enemies, she would try to end us. -If Mystra tells Gale she would fuck him if he explode us, he probably enthusiastically will. -I haven't played much with Wyll, but i think he would torture us for some sloppy seconds with his devil. -If Astarion get's a bit thirsty, he will take a sip, courtesy of the house.
But even in this little piece of the game you can start seeing what is underneath our companions.
I liked Lae'Zel a lot more after her dissapointment when we find, and kill, de Gith patrol, she starts feeling more at home with us than among her people. Shadowheart has a lot of momments where she open's up, she is heavily confused, in a way she seems almost to be faking. I tried an evil run, and when you do the party after the slaughter she is particularly conflicted.
And so on. The game crearly is setting a path for them to gradually change. I didn't like most of them at first, which for the game is on purpose, but as I knew them more, and more, they grown on me.
