You are kind of all over the place. You initially accepted that the back wound was shallow, and that the three shots could be explained. You said, the first created the shallow back wound, the second hit Connolly and the third hit Kennedy. But one of the bullets missed the limousine. So now you are stuck with the single bullet theory, Connolly not reacting to his wounds, and an entrance wound in the President's neck that you can't explain.
For Oswald to be the LONE assassin, the single bullet theory MUST work. But it doesn't work. From a ballistic standpoint; the initial entry wound in the President's BACK is lower than the exit wound in the president throat. And it doesn't work neurologically. The only way Governor Connolly's reaction to his grave, massive, invasive and sudden wounds could be delayed, as the Warren Report claims is if Connolly was a quadriplegic or so heavily sedated that it would put him in a semi-comatose state.
The evidence that the last two shots were fired almost simultaneously comes from a multitude of witnesses, from Secret Service agents, police, media members, politicians, and bystanders that were there.