For number 4, would Ainu work? I doubt there would be any Americans familiar with it.
The first American-sponsored college in Japan was in Hokkaido, if I recall correctly, so there are likely to be some people with knowledge of it. Considering the number of languages the Japanese would have to pick from, it'd be easier to narrow down.
Not to say it won't be effective at first, but it has more of a risk of being broken.
Step 1: Cripple the everloving shit out of the US Navy. The Pearl Harbor attack could have gone on a lot longer and turned Oahu into a smoldering crater if the Japanese were up for it and had been better prepared. It would have been a week that lived in infamy, and no matter how pissed off America was, it would have taken a LOT of time to build up a counterattack.
So, use up all the Japanese fuel either station keeping or fleeing from American submarines
and the American carriers who will be able to eventually find the Japanese carriers, who have been attrited of aircraft, munitions, and aviation fuel? The Japanese lost "only" 29 planes in the first two waves - and they will continue to lose more with every wave attack. That's not to mention the airframe casualties you'll experience by constant, round the clock attacks with maintenance issues and pilot exhaustion cropping up. So you will eventually destroy your premier strike force and lose the advantage it provided even if the American carriers don't find you. And if they do, then you'll have an exhausted CAP running on the last vestiges of fuel to defend the Kido Butai, which will probably go about as well as can be expected.
Step 2: Tojo makes sure Hitler slows his roll against the US. Keep the British, French and Russians busy with the Nazis and handle business against the Americans one-on-one.
Which doesn't help the Japanese at all, as the Japanese then are not getting access to any of the oil that they need. And this provides more time for the UK and Dutch to get their act together as well. So not only will the Japanese be dipping into its reserves earlier with no hopes of recovering it by driving the US out of the Philippines, they will
And in the end, this means that
all US Naval Forces can be committed to Japan, at least at the start, which means more American flattops at the start being shifted west.
Step 3: Until the end, America always envisioned the war with Japan (which they expected in full) to be almost exclusively naval. So stymie the Americans in enough battles that the tide doesn’t turn and the Americans can go no further.
Which of course won't matter past late 1943, as by that point the US will have amassed a critical mass of new carriers that are better and carry more aircraft than the Japanese ones and are equipped with aircraft that are superior to Japan's aircraft, and in greater numbers. 32 Essex, 6 Midway, the 10 Independence and 2 Saipan, and that's just OTL numbers of planned vessels - if the war went South, you'd see some more conversions of the cruisers and battleships (both the Alaska class and Iowa class had plans drawn up just in case). And the Japanese would be doing what? Attempting to invade New Caledonia (not happening based on the Japanese planned numbers for the invasion and the number of defenders). Attempting to invade Port Moresby? Australia?
The Japanese, after the battle of Midway and by the end of 1944, would have built 3 additional fleet carriers and converted 2 light carriers - the US would have built 12 fleet carriers and converted 9 light carriers. You'd be talking about a 4-1 kill ratio, using subpar equipment and aircraft,
just to break even.
Step 4: With America frustrated that they can’t even beat the fucking Japanese straight-up, wait for an isolationist to get elected and for isolationist GOP members to take Congress. End the war, watch America curl back up in its shell, and hope to hell the Nazis handles business against the Russians. If they did, skip to Step 6.
And the old fallback of Japan - hope you punch the Americans hard enough that they sue for peace, hope that our might ships can never be sunk, and defeat their huge submarine fleet from strangling the empire. You're conflating a Vietnam War-era America fighting a French colonial war vs a major strategic war against a geopolitical rival who has occupied American soil. I doubt they'd be so easy to fold.
Especially as these victories
will require 100% success of the Japanese, every time. As trading 1 for 1 isn't an option. Trading 2 for 1 isn't an option. Even trading 3 for 1 isn't an option.
Step 5: Get ready for the Russians. Remember what worked in the dawn of the 20th century and use it. Plunder the mainland of Asia and keep the people out of the way as much as possible.
What worked in 1905 won't work in 1944, especially as the Russians will be mechanized to a larger degree than the IJN and will have better armor.
There is also the pesky problem of the Chinese, and you have created another two-front war for yourself. Oh, and you STILL don't have any oil, as the US hasn't ended their embargo and the Dutch and British territories haven't been conquered.
It wouldn't win the war for Japan but getting the US to go to war with Germany in the winter/spring of 1940/41 would help the Japanese substantially as the main strength of the US pre war professional military would be busy deploying to Europe and North Africa. It would at least delay the US's ability to at first resist and later to strike back against the Japanese Empire. It also gives the Germans and Italians several months to give the Americans a bloody nose like sinking a carrier or two in the Atlantic/Med.
The US being busy with the Germans might make them more cautious in their dealings with the Japanese perhaps even reducing/eliminating the oil embargo. They might even let their guard down more than OTL as commanders of quality do their best to get transferred to the war in Europe making the Pacific a command quality backwater.
Of course being at war for half a year means the US would already be starting to flex its industrial and manpower muscles so this might not be such a game changer as it first appears. Although if the Japanese could only wait until the Americans commit themselves to a major invasion followed by full on ground war in continental Europe then all bets are off.
This is pretty much OTL; the US committed the majority of their forces to fighting the Germans, as they were by far the most dangerous enemy. The Japanese were, at best, a thorn in the American's side from a strategic level, because they could never do anything to threaten the American industrial base that was pumping out more material than the Japanese could dream of. And the Germans and Italians did not have a sufficient fleet to tie down major fleet elements (and the elements used in support of landing operations would, for the most part, be obsolete warships).
At best, you'd catch them out of position. But already mobilizing a year or two earlier, so troop levels would not differ.
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The best way for the Japanese to win is by attacking Pearl Harbor with a Publicity Blitz after successfully negotiating a ceasefire with China at 1931 borders, with Japan only maintaining Manchukuo after coming to terms with a new leader to form an anti-comintern pact in East Asia to fight the Chinese communists and keep them from subverting both Japanese and Chinese territory.
Then the War for American Support, the code name for Japan's publicity drive, gets under way.
