CalBear-This simply not true, any of it.
The Japanese had figured out EXACTLY where the Kyushu landings were going to occur. They had managed to move over hundreds of thousands of fully armed armed troops into position (including several rock solid Kwantung Army divisions) and had better than 11,000 aircraft ready for kamikazi attacks (This included a number of older trainers that were mainly wooden construction and, as the Japanese discovered accidentally, were much more difficult to 1) pick up on radar & 2) lacked enough metal to set off the proximity fuses that were so effective in killing regular kamikazis. These aircraft would have been a particular pain in the neck at night, and the Japanese had planned to use instructors who were night qualified in that role.) as well as 2,500 suicide speedboats. The Japanese had also made a decision that they would finally stop targeting carriers and battleships and go after the really important targets, the troop ships.
What is REALLY scary is the the U.S. didn't know that there was this level of opposition available. The RN/USN had tried to sucker the Japanese into attacking the fleet when the bombarded the Home Islands, but the Japanese didn't bite. The Allies decided that they didn't react because they couldn't. They didn't react because the knew they had finite resources and they were going to wait until the latest version of the "Decisive Battle" was in the offing. They were not finding the suicide boats do the figured there werent any. They figured that the Japanese had about half the aircraft and less than half the troops available on Kyushu that were actually there. They had no idea that the defenders in Southern Kyushu actually outnumbered the assault forces (although to be fair, the last Intel was showing a LOT more IJA troops on Kyushu than expected)
Japan was beginning to starve, but was NOT yet in full on famine with bodies piling up in the streets. It would certainly have gotten to that point, but that was well into 1946, and certainly not have forced a surrender before late 1946-early 1947, or after both Olympic and Coronet were planned.
The same can be said for the bombing offensive. There were almost no makor cities left to hit once the "reserved" list was finished. The AAF was planning to start hitting cities of 40,000 population or less simply because there was nothing else left worth hitting. There would have been many casualties, probably ranging into the millions if the war had continued into mid 1946, but if the destruction over every major city in Japan, plus two nuclear attacks, wsn't enough to put the Japanese at the table, the destruction of towns wasn't going to do it either. It is also unlikely that more than one, at the most two, addtional weapons would have been expended against city targets. General Marshall had decided that he would use the 7-10 weapons that would be ready by the time of Olympic in the tactical role (yes, that is as crazy as it sounds to our modern ears, but at the time it made sense).
The Navy, especially Admiral King, WANTED to block and bomb, but they were still in the minority. The President and his advisors were resigned to invasion, and while there is always the chance that the October 1945 typhoons would have caused enough delay that the Japanese would have fallen over, it was not part of the Plan.
There has been a LOT of revisionist history on this subject, most of it is totally wrong. Downfall was going to happen. Even though the "let 'em starve" strategy had proponents none of them were named Truman.
You missed something rather important about the Kamikazes; despite throwing away (literally) the lives of thousands of young Japanese, the number of Kamikazes you qouted would have only scored 1540 hits on the Allied fleet. Now assuming, and this is a big assumption, that every single one of these hit one ship each (which they most defenitely wouldn't have), they would have sunk 131 ships... this isn't even remotely enough to stop the Americans. For all their alleged bravery, the kamikaze pilots would have done nothing to help the Japanese in the event of an invasion that was never going to come anyway.
This goes back to the issue of the invasion itself, it was not necessary, it was not going to end the war quicker and it was not going to happen. The third nuclear bomb would have ensured this, most probably, because it would have been aimed at Tokyo. In the process, the Japanese high command would have been gone and either the Japanese simply would have stopped fighting (you may wish to note that the Americans spent many of the early months of the occupation defending Japanese soldiers from vengeful civilians) or anyone with the necessary authority left would have surrendered the country. There is only one situation where I think Truman would have ordered an American invasion of Japan, which would have been to head off the Russians if they landed on Hokkadio. After the bombs were dropped, Downfall was a waste of lives and besides, Japanese resistance was utterly futile.