The pedo had a very large chain that he was trying to brain Kyle with, so yeah, that IS attempted murder. Kyle heard a shot immediately behind him, so he turned and saw the pedo in close proximity. It is logical to assume the shot came from the obviously violent person TRYING TO CATCH YOU! So Kyle shot him. Self defense, no question.
Huber first tried to stomp Kyles head while he was lying on the ground, then he tried to brain Kyle with his skateboard, if you think that you can't get killed by a skateboard then you are a fool, then he tried to take Kyles gun, that is when Kyle shot him. Once again, self defense.
grosskreutz first backed up, then tried to get around Kyle to place his pistol against Kyles head (very clear in the videos) and Kyle shoots him in the arm. Once again self defense.
You have to be intellectually dishonest to watch the videos and claim that Kyle is an active shooter.