My definition of victimhood is the conventional one, and how it is used in a formal context.
It also addresses externalities, by distinguishing nonconsensual acts from consensual ones. If a person deliberately over-eats, and dies from obesity related illness, they are not a victim, and their family's loss is not an externality, as the term is defined in economics. If a person is shot and killed by an armed robber, they are a victim, and their family's pain and suffering is an externality.
The reason the former is not an externality is that the 'asset' which the third parties lose, which, let's say, is the love and care the individual would have given their family if they had stayed alive, was destroyed by the wilful acts of that individual. Since the love and care is the individual's to give, it is also the individual's to choose to not give. Their decision to not give it is therefore not an externality.
In the case of the latter, the victim had every intention of giving their love and care to their family for many years to come, and would have done so, if their individual rights had not been violated in the act of murder that they were the victim of.
This is a coherent moral framework that is consistent with the definition of both 'victim' and 'externality', and exactly how the justice system sees victimhood and damages.
>>I think you're going to have trouble selling your moral framework as anything but a Randian fantasy of callous self-determination.
Comments like this don't really add anything to the discussion, except perhaps revealing your own presuppositions and ideological biases.