Good question. When you find someone who believes in libertarian free will, let me know. Until then, this is little more than theological self-gratification.
What we have done is establish a basic premise. That premise that:
-- Person A's unfaithfulness will prevent zero elect from regeneration. The converse of that is: Person A's faithfulness is not necessary. That is the basis of the accusation that calvinism is not concerned with evangelism, and is the basis of those calvinistic groups that discourage evangelism because it is unnecessary. The problem, of course, is that the calvinists will claim that they have affirmed the "duty" of Christians to proclaim, and that somewhere in the decree of God there might be a rationale for this duty that in which it might make a difference that cannot be defined in this realm.
Regarding Free Will one can say that: Person A's faithfulness might assist one of the "any who will believe" to come to regeneration. This is the basis of the accusation that free will advocates think that they are responsible for someone's salvation. Again, it over-reaches because it does not recognize the word "assist" and replaces it with the idea that the believer is "responsible for."