Alistair and Wynne are pretty clearly 'good'. Their behaviour and opinions match that of the 'good' party members we've seen in Bio, Obsid and BIS RPGs over the last decade. The likes of Leliana and Sten are more ambiguous, and Alistair is hardly Carth, but it's a fair call to make I think.
I think they still do a good job of sticking to their convictions though. Wynne retaliates at the Urn, Alistair doesn't. There's a fair bit of times that Alistair doesn't mind a whole lot if you do more evil things, I assume because he's understanding of what it takes to fight the blight as a Grey Warden. Trained as a Templar though, he'll have issues with things like using Blood Magic.
Alistair supports you being heroic, but doesn't mind if you do unheroic things a lot of the time. He's mostly indifferent. On the whole, Leliana is pretty "good" too, but they often have their rationalizations for the odd circumstances.
Wynne definitely fits the "good" one the tightest, IMO, though I'm surprised that she's okay with the scene I'm describing. Maybe because it involves a Templar. I don't remember her dialogue.