I don't have an opinion one way or another as I am not very familiar with argumentation ethics, but what defines an economic actor?
Personally, I would base on it whether a being is self-aware, or maybe whether a being is capable of self-awareness. Maybe economic actor covers this.
I am also undecided on whether I view babies or people in comas has having self-ownership. At some point there has to be a transfer of power or the entire structure of society turns into an ad hoc legal system.
In your thought experiment about aliens, you pose it in terms of a negative. That is, what criteria need to be met to justify killing another being/species.
What about the alternative? Suppose an alien race is to us as we are to worms. What criteria need to be met for them to do something to us that will benefit all of humanity? Are there any? Suppose their intellect is so much higher than ours we cannot comprehend their form of communication.
this territory is moderated
I'm using "economic actor" to mean an intentional user of scarce means to achieve desired ends. It seems to me that only economic actors could have a dispute.
Babies and young children are a really tricky case for most philosophical systems. Are they full persons, parental property, something else? I'll leave them for another discussion.
People in comas are still treated as property owners. The point isn't that they are incapable of arguing, but rather that we can reason about property titles and whether the person in the coma has the better claim to disputed property. If they have no one to argue on their behalf, then there's essentially no dispute: there would just be someone else using their stuff uncontested. Upon waking from the coma, the person could reassert their property claims.
What criteria need to be met for them to do something to us that will benefit all of humanity?
Am I understanding correctly that the super advanced aliens want to help us? Maybe mass medication or something like that? I guess I'd want to know if they have a better philosophical basis for doing so than our Argumentation Ethics. Presumably, they do have more advanced philosophy, so maybe I'd be convinced by whatever their reasons are. Since I'm not privy to that hypothetical philosophy, I would say they need to limit their interventions to people who opt in.
I'll add that not only can we not understand their communication, they may not understand ours. This would be very similar to our situation with the animals of our planet.