Self-defense with lethal force is only defined for threat of imminent force, and only if that threat is proportional to the force you bring to the table. If you pull a RIF on an unarmed burglar, you are bringing what is apparently lethal force to what is at best property crime.

When I said "present", I was referring to "presentation", as in brandishing. You aren't allowed to do that.

You are allowed to use it, in a situation that calls for immediate force, but since there are regulations on proper gun storage, it's basically a minor exception for people who manage to rush to their gun room, unlock and retrieve the (unloaded) gun, unlock and retrieve ammo, and then load/chamber/fire said ammo.

Which is unlikely.

The thing that resulted in his conviction was not premeditation, but proportionality of force and legality of gun ownership.

You're not allowed to use lethal force to defend property, only life.

"Offensive weapon" legislation is exactly that. It pre-empts justification and only requires a prosecutor to prove that you had a harmful weapon available on/near your person. It's essentially at their discretion whether or not to convict.