Yours is a scary scenario. But I do have a question or two.
What makes it so hard for Israel to hit back at NK?
There's no doubt that Israel's missile technology is more reliable than NK's. Do they not have missiles with enough range?
Israel's strength lies in their air superiority over their neighbors. As far as I know they do not have an Aircraft Carrier. They had a hard enough time making it to Iraq and back, when they bombed the nuclear reactor there. I don't know if they have missiles with the distance to reach North Korea, but they definately can't get their planes there.