Just say what you think is ASB about the Hawaii situation so we can talk about it rather than doing the alt-history equivalent of
this. It's more fun if people are actually capable of having a back and forth conversation on the board.
I'm just saying that unlike the Phillippines where hatred of the US was pretty much universal, in Hawaii there would have been a significant number of people who would have remained loyal to the United States. Most of these would have probably been white admittedly, as they stand the most to lose in terms of finances, their lives, etc, but nonetheless the way you depict it once the Hawaiians decided to declare their own independence they were simply shunted aside without a fuss. With significant naval bases within reach of these loyalists, they would have definitely fought first before throwing in the towel. There would also be a number of individuals of Asian ethnicity that would also side with the loyalists in the hope that fighting against the rebels would grant them better rights as US Citizens.
Furthermore, you simplify things by mentioning that just because Hawaii has a significant Japanese population, that these people would welcome Japanese intervention with open arms. Hawaii is a hodgepodge of ethnicities, which include Chinese and Koreans, neither of which has much reason to like Japan, especially the Koreans. Furthermore, we know just how racist that the Americans are, but so are the Japanese, especially toward Koreans. That is balanced by the admission that the 5 Corporations basically ran Hawaii like a plantation, but nonetheless Expat, I get the impression that you papered over the immense racial challenges that the Hawaiian Independance movement would have had to overcome to acheieve the sort of unity necessary to be recognized as an independent state.
Basically, I'm not sure that the rebel leaders speak for all Hawaiians on the entire chain, just like the Founding Fathers of the United States didn't necessarily speak for all American colonials in the 13 colonies, for there were a significant number of loyalists who fought to remain with the Empire as hard as those who sought to free themselves from it.
Another thing you underestimate is that the Hawaiian Rebels would have problems coordinating with one another given that Hawaii is an island chain. While Japan can bring a fleet to Hawaii, the only port, Pearl Harbor, is still in US hands, and once Japan leaves the US can move back in and support the loyalists to take back Hawaii.
Furthermore, Japan would not be able to openly aid the rebels before Hawaii is given international recognition as a sovereign state, but given that the USA is on the world's shit list that shouldn't be too much of a problem. I also argue whether Japan can actually carry out such a big mission and put such a show of force in Hawaii. I know about Pearl Harbor OTL, but until a few months ago there was seemingly no inclination that Hawaii was about to rebel, and also given the fact that Japan was investing much of its resources into the Phillippines, its difficult to imagine that it took Japan a mere few months to plan such a mammoth 'relief' operation from scratch. The logistics of this are also huge, since they have no bases in which to station their fleet, as they can't merely stay around the islands forever and sooner or later would hae to refuel, and because last time I checked, Midway and Wake islands are still US territories among others, as is Pearl Harbor and the closest base is the Phillippines. Once the fleet inevitably has to turn back, the US can issue reprisals against the Hawaiian rebels, and then the Japanese will decide whether its worth going to war with the US over Hawaii, and when Japan comes back they'd have to attack the US. Or there's the possibility that a Middle African sub will brave the journey to Hawaii and attack either a US or Japanese vessel in hopes of starting a war between the US and Japan.
As for Japan, being labeled the 'liberators of the Pacfic', as I mentioned earlier sooner or later they're going to have confront the reality of the contradiction that is Korea, which again is still ruled in the most draconian style. You can mention, oh Japan will just liberalize its rule on Korea, but that can't be done easily. There is a different dynamic when it comes to Korea, a level of disdain that exists in the minds of Japanese at large that merely removing the militarists from power won't remove. The militarists would reason that the moment the civilian government gives an inch on Korea, China/Russia would immediately step in and spark a rebellion, and frankly its a reasonable argument.
Lastly, I understand full well that many people on this timeline don't like what I have to say, because it seems like I'm supporting racists and bigots, and that arguing the case for the US is not a popular stance to take. However, my recent concern is that because many of the readers are more than happy to see the United States go down the drain, the writers of the TL would be influenced by their sentiments and compromise the integrity of the storyline at large to meet their expectations. For instance, the US has made a whole host of negative and boneheaded actions, which taken by themselves can seem plausible, but when put all together one after another and looked at as a whole its not as much.
Then again, Nazi Germany existed in OTL, but if I were in an alternate TL in which Germany lost the Great War and wrote a timeline where Germany proceeded to go Nazi, you'd all say ASB or at least call my storyline utterly implausible. Again, what's happening to the US isn't ASB but probably the worst case scenario, a low probability event where everything has to break exactly wrong for it to take place.