Seems the Mossad should just step up an assassination campaign. Maybe you can’t take out the underground facilities, so you take out the scientist and the grunts working the centrifuges.
Yes.
Since the physical assets are pretty well scattered and buried, it is likely that command and control would be the main targets. Israelis do know where these guys live.
BTW, to see what 50-year old nuke technology can do, check out what could be put in an American seaport:
http://www.freerepublic.com/focus/f-chat/3274924/posts