"The whole inspection proceedure was of course a red herring, as we had already decided we were going in legally or illegally..Ake"

Hardly a red-herring Ake, it was only because of GWB and the US Goverments efforts that the UNMOVIC Inspectors were invited back into Iraq.

Had the US developed a plan of attack prior to that? I would be very surprised indeed if they had not. The planning for that possibility would have been run on continuously since Safwan by various planning staffs - that is after all what they do. I have no doubt that the US has plans for invading Iceland and Ireland (both neutral countries) - doesn't mean that they are going to do it any time in the near future.