Wow, Benway, that's extremely helpful information -- straight from the fish's mouth, as it were!
Speaking of salmon, I think I mentioned somewhere that raw salmon is not at all popular, and in fact fairly unusual, in Japan. That's because of the parasite problem you mention. On the other hand, of course, salmon is extremely common and popular in American sushi places. Why? Because American sushi places normally serve defrosted fish, and American diners are not used to what truly raw fish is like.
You're dead right about octopus sashimi. Some people in Japan want the tentacles still squirming, which means cutting the slices from a live octopus. The cruelty part doesn't concern me much, but personally I don't like my food to move in my mouth. Besides, the suckers tend to try to seize onto your tongue, lips, and inner cheeks, which I find gross.