It might be a challenge to find. My local butcher has it, but I’ve seen at Whole Foods. A2 milk has proteins in that make it easier to digest. I drink regular store milk but only make yogurt with it. Bought the initial strain off Amazon but save the whey to make the next batch.
Greek Yoghurt does contain lactose, according to many reasonably reliable sources.
Not as much as sour cream, I think, but definitely some. Depends on how severe your intolerance is, perhaps?