Yes, Domri is OP and I want him.
Um, I'm not sure. I heard it was the five current blocks. That would make it Gatecrash, Return to Ravnica, M13, Avacyn Restored, and Dark Ascension. But I think they leave the whole block in, so Innistrad might be Standard too.
Ok, no. According to
this it's the two newest story blocks and one core set, so all of Innistrad should still be Standard. I don't know, I don't play tourneys.