I doubt he was ever "rebuffed", unlike Clintoon.
And on 11-22-63, Kennedy was probably wearing a bullet-proof vest. Since there were at least two excellent marksmen that day, the vest didn't do him much good.
No. Why don't you do some research instead of dreaming something up? There were three shots fired and the witnesses on the fifth floor heard Oswald fire them. They even testified that they heard the brass hit the floor with dust from the ceiling falling on their heads. The trajectories from Kennedy were measured within 9 feet of the sixth floor.