The most obvious omission to this theory is you do not take into account the effect of the muzzle blast on the SS men located around the rifle. Specifically, the men in front. Having someone fire the rifle near their heads would have somewhat rung their bell and made their ears ring. They show absolutely no reaction at all, let alone the discomfort level of having someone fire a gun that close to their ears, and not a mention of a shot being fired in anyone’s statements, let alone 4 shots.
You have it right with LHO firing only two shots. Those two shots explain and answer all questions for the entire assassination.
The SS is a brotherhood. I'll believe anything any of them says or FAILS to say when SA Clint Hill admits that the JFK Limo came to a STOP at some point before reaching Parkland Hospital. This is when Motorcycle Officer Chaney caught up to the Lead Car and told Chief Curry the condition of JFK inside the Limo. To this day, Clint Hill continues claiming the JFK Limo went non-stop to Parkland Hospital. That is pure

and as a result, everything Hill says needs to be looked at closely.
Regarding the possible discharge of the AR-15 by SA Hickey, the most damning evidence proving this is 3 different people smelling Gun Powder as the Queen Mary traveled down Elm St. This includes DPD Cop Smith smelling gun powder way down inside the Parking Lot, along with Mrs Cabell, and Sen Yarborough. Yarborough claimed he smelled gun powder almost all the way to Parkland Hospital and he was riding in the car directly behind the Queen Mary which Hickey sat inside.