Occam’s Razor…..simplest complete scenario.
My guess is that Crooks killed the fire chief, wounded the other two men, and hit the bleacher railing and the hydraulic hose. The actual sniper fired three rounds in rapid succession just as Trump turned his head. Finally, the defensive sniper shot Crooks dead.
And ballistics will never be revealed.
But I don’t know about anything.
I second your description. I doubt if the kid was such a great shot.