I say the shooting was legally justified. One could also say that the officers fired because they knew they had a clear shot vs just a few seconds ago where they were pointing their firearms at the crowd behind. I think the handcuffing was inappropriate in this situation.
I suppose it depends on the department but most PD's policy is shoot to stop the threat. I would have thought, being that the two of them were in the same car, a point man would have been selected. Namely the officer on the right should have made the kill. However the guy is on the ground and the officer on the left still shot him twice more. Tasers are not an option as this PD doesn't have them nor allows them.
It was a legal kill but poorly executed.
I think the Mike Brown shooting is probably a more legitimate use of lethal force based on the little speculation we've heard.