Erect dummy flight decks or turrets and superstructure on expendable old ships. If the dummy is the right size and shape, it would pass. Nobody had "good aerial reconnaissance" in 1941-1942. Certainly not got enough to see through a well-made disguise on a brief pass at long range .Building "dummy" carriers and battleships. How would the Japanese go about this? And given the U.S. had good aerial reconnaissance I should think the U.S.N. would recognize a fake carrier or battleship from a real one.
Then if the US attacks and sinks a dummy, are the US attackers going to report anything other than "SCRATCH ONE FLATTOP" or "SCRATCH ONE BATTLEWAGON"? (Air attack only; the Japanese are smart enough to keep the dummy ships out of surface action range. Or a sub gets lucky - the view from a periscope is very limited.)
I guess you missed the part about releasing all civilian internees and sick or wounded PoWs with strictly humane and respectful treatment to report. At which point all atrocity stories (actually rumors based on fragmentary reports from random neutrals and escapees) are exploded. At that point, many Americans would recall the "Beastly Hun" propaganda of WW I, which exaggerated German misconduct so wildly that many people even today think it was all lies. A key element of the isolationist narrative was that the US had been tricked into joining WW I by such British lies.Pretending to abuse U.S. P.O.W.s would only enrage and galvanize support behind the war effort. The reports of the atrocities inflicted by the Japanese during the Bataan Death March to name only one fueled the hatred the Americans felt for Japanese after Pearl Harbor. News of such atrocities would serve to harden American resolve so even if the American fleet suffered a disastrous mauling the Americans would still be united against a perceived evil enemy.
And if the US stays out, so much the better for Japan.Invading Malaya, Borneo, and the rest of South East Asia does not necessarily guarantee the U.S. entry into war.
They were afraid the US would go to war against them, so they made sure the US would go to war against them... Can we agree this was not a sensible line of thought? The US forces in the Philippines were very weak, and no real danger to the Japanese offensive. If the US declared war, that would be time to crush the Philippines.On the other hand, from Japan's point of view they couldn't leave the Philippines as they were because they feared America would declare war and move to cut off Japanese supply lines to the south.
Of course if Japan kept strictly hands off, the US could build up a powerful force in the Philippines - but it would take at least six months if the US started sending everything available there.