>>> They probably also wanted a back rub and a V-8, it is immaterial. <<<
I think that you are in error. This WAS far from being immaterial to them. The Japanese military was far from being blase about their territorial acquisitions during the Pacific War (not to mention Taiwan and Korea). You know, acquisitions paid for with their country’s blood and treasure. You’re also ignoring the important distinction between “the person of the emperor” and “the imperial system.”
After reading historians ranging from Robert Butow to Richard Frank, it’s pretty clear to me that the Showa Emperor and the militarists in Japan were not in agreement amongst themsleves as to what conditions of surrender would be acceptable. Even after the Potsdam Declaration. You are greatly oversimplifying matters.
>>> the US was perfectly willing to scrap any plan to remove said emperor to ensure a more peaceful occupation. <<<
By “the US,” do you mean Asst. Secs. of State Dean Acheson and Archibald MacLeish? And the majority of US citizens and Congressmen in 1945? You must be joking.
The emperor accepted unconditional surrender; ergo, he would have accepted conditional surrender that left him nominally in power too. Many of his officers did not accept the first and were willing to use force trying to stop it. Many of them would have accepted the second. Actual control for any of them was out of the question and they knew it, they were going to be slaughtered if they continued to resist and they knew that too. There were just several things they were perfectly willing to die for, and one of them was what they thought of as the honor of their emperor, which the shinto cult raised to a god figure. Which did not have any connotation of actual command, given Japan's past, but did have one as a figurehead that warriors gave lives for.
Regardless of whether the emperor would have accepted such an offer without the bombings, it was the clear duty of the US leadership to offer it before using them, since it did not in fact require the removal of the emperor as a political aim of the war.
By "the US" I do not mean two men you name, I mean General MacArthur and our actual policy during the occupation. You know, what we actually did. We left the emperor to make it easier to rule Japan. If that farsighted policy had been adopted very slightly earlier, it could have been offered before the bombing - as Grew (the ambassador to Japan) and Stimson (secretary of war) both urged at the time. Stimson in particular did not know if it would work, but thought is blatantly obvious that it was worth trying. It might save hundreds of thousands of lives and it would cost nothing whatever.
Truman overruled him. It was an unwarranted and wanton decision. Stimson was right, and Truman was wrong. Morally. And this was clear at the time, it is not hindsight.