Is there a debate about this in Japan?
For what it’s worth, the “Health” (衛生) section on Wikipedia mentions bacteria due to lack of gloves, but to my eyes does not mention pregnancy.
The proscription is mostly about large fish like tuna that eat many smaller organisms and accumulate mercury. Otherwise, completely avoiding sushi (or really raw fish in general including sashimi) is a bit excessive (IMHO).
The short answer is: no there is no debate. The general consensus is that it’s probably best to avoid raw fish, but people don’t make a big deal out of it. Remember, this is a country where serving chicken sashimi is perfectly legal.
Sushi means the way the rice is cooked and presented, not “raw fish,” so no.
My Taiwanese wife and I lived in Japan during her pregnancies, and eating sushi was discouraged by her Japanese friends.
Yes - but essentially every definition of the term includes a mention of raw fish.
Although raw is the traditional way, it can be cooked as well, even in Japan if the Engrish in my link is to be believed. Stuff like unagi normally is, although I think you might see in more often in things like unadon than rolls?