Anthony Zerbe's character, maybe I'm missing something?

I just watched this film this morning, is there some significance, or a reason, maybe in the book, why the news anchor we see in the flashbacks turns out to the the "Family's" leader? Is it just a coincidence?

I'm going to preface this thought with the acknowledgement that I may be thinking *way* too hard about this, but...is it possible that the flashbacks we see are actually how Neville is supposed to be remembering events, and in the couple of years since the events, he's forgotten the face of the actual anchorman, and has simply superimposed what he thinks a pre-plague Mathias' face would have looked like, onto him? In other words, we're not seeing the true events, just his memory of them?

Were the filmmakers merely saving money, not having to hire a separate actor?

Also, Neville refers to himself as "immune," and to a "vaccine," but we see the helicopter pilot begin to exhibit symptoms, and moments later, Neville as well, then the helicopter crashes, and Neville injects himself with the "vaccine" and is cured. Can something be both a "cure" and a "vaccine"? I don't argue that a cured Neville could produce antibodies.