The biggest difficulty with moving the Pacific War around is the window where Japan had the smallest chance of success is so small. They needed six decks to deal with the Pearl Harbor attack; it was a miracle that the Shokaku & Zuikaku were both worked up and ready by 12/7/41 as was (Zuikaku was in commission for just 60 days when it set off with the rest of the Kido Butai).
The Zero wasn't available in numbers until mid 1941, prior to that date the A5M was the primary IJN carrier fighter and there were exactly ZERO D3A in the as late as mid 1940 leaving the dive bomber duties to the D1A with its smaller bomb load and 500 mile range as the fleet dive bomber. This would have forced the Fleet to move within 100 miles of Pearl Harbor to amke its attack, assuming that any attack would even be attempted.