I like e discussion so far and I see your points. Hiding the battleships is not easy indeed.
Now, let me think this over: What if Japan did not want to hide the battleships. What if they recognized earlier on, that aircraft carriers were the most important ships in the war to come and that hitting the fleet at anchor in Pearl harbor would not destroy whatever US ships were found there, but allow them to be salvaged?
What if the Japanese decided for the "decisive battle" to happen immediately at the beginning of the war, when the USN was less prepared?
So, instead of going after Pearl harbor with the Kido Butai, the Japanese split their forces. One force of 6 battleships, a couple of light cruisers and a dozen destroyers goes straight for Hawaii, aiming to tempt Kimmel in sending his battleline out and commit his CVs. Soryu and Hiryu are escorting this force, carrying mostly Zeros.
This force is the bait and it is used to shell Wake island on the 5th of December. Enterprise is on its way to Wake island, but steams away towards Pearl, having little to offer alone.
The Lexington mission is also scrapped and she's being loaded with her normal complement of planes. The Japanese start moving towards Hawaii on the 6th if December, US subs are sent towards the task force and PBYs try to locate the task force, only to be shot down by Zeros. A B17 strike achieves little from high altitude, but the Japanese lose 4 Zeros, realising that the B17 is a tougn nut to crack with machine guns only.
The decisive battle takes place at the 7 of December around 300 miles off Hawaii. The US battleline is there, together with Enterprise and Lexington. Both armadas clash, the USN having clearly superiority in numbers, aided as well by the USAAF operating out of Hawaii.
Suddenly over 300 IJN aircraft appear coming from the North, launched by the so far undetected Kido Butai. The USN radars on the carriers pick them up (did both of them have one?) but it's too late to divert sufficient fighters against them. At the end of the day, the IJN bait force has lost 4 of the 6 battleships, both small carriers, both light cruisers and half a dozen destroyers. The Kido Butai has only one carrier damaged from a USN sub attack.
The USN has lost 5 battleships, both Enterprise and Lexington, a dozen destroyers and half a dozen cruisers.
Strategically pre-placed IJN subs played a major role in the operation, hitting 2 battleships as they left Pearl harbor.
So, what do you think?