Yes, I'd agree that they're all grammatical. I can't see any difference between 1) and 3) except that 3) might be a bit more common in everyday speech since it's shortest I would say that 2) sounds a bit more formal and you would be less likely to hear people say it that way (in Australia, anyway). It might be preferable in formal writing though. Well, that's just my opinion. They're certainly all very similar.