Regardless, the basic question remains, were there any other less lethal options that the law enforcement officer could have utilized to regain control of the situation in both what happened in Mililani and at the capitol. From all available facts made open to the public, arguments can be made that there was that possibility. In both cases, neither suspect were armed with guns, while that was not true of the officers involved.
If a civilian in Hawaii decided to use their firearm to defend themselves on their property from an attempted assault from someone who was not armed and it was known the civilian actually had pepper spray and a baton on their person that they could have utilized, instead of their firearm, I would wager that person will still be facing murder/manslaughter charges from the prosecutors office.
There will always be a less lethal option but it doesn't make it a good option. For example, if someone were coming at you with a knife there would always be the option that you could use open hand techniques to disarm him but it is dangerous and unreasonable to expect you to take that option.
Now I haven't read heavily into the shooting at the capital but if I understand correclty the suspect had put the sheriff in a choke hold of some sort?
Are there escapes to choke holds? Yes but unless one is proficient it isn't going to be a realistic option.
Is pepper spray or a taser a viable option? Taser is going to be difficult if the person was at your rear and pepper spray might work though you risk exposing yourself.
Baton? Harder to hit the safer impact points on someone behind you and hitting them in the head is still risky and could be lethal.
The downside to these options are that you have a very limited amount of time if someone has the choke on good, maybe 4 seconds if it is perfectly applied. If you elect to try these other less lethal options but they fail, you might not have ability to upgrade to the lethal option before passing out/dying.
A regular civilian would nearly always be arrested if they killed another person because that would be a homicide. That doesn't mean the civilian can't claim self defense and the burden of proof is on the prosecutors to prove the person wasn't acting in self defense. Yes, cops do get a pass here but it is in the beginning. Cops get a certain benefit of doubt that they were doing their job properly and then prosecutors consider the evidence and decide whether or not to charge the officer with a crime. It doesn't mean the civilian faces a different level of proof though.