Like my students say, I'm not very good at multiple choice questions....
A few opinions. First, I think the first cluster of options that Peter offers presumes (option c) that values matter. And, indeed, research suggests that they do--but not nearly so much as we assume. That is, if you measure values as traditionally measured by psychologists you can only make weak predictions about behavior. I think the weakness of links between values and behavior is one rationale for exploring the possibility that identity is a useful construct, as it might help us fill in the gap. So, for example, people tend to volunteer for a particular cause; as Pilavin points out, blood donors may begin as people who have only weak inclinations towards and thoughts about blood donation, but after years of commitment they construct images of themselves in which blood donation is fairly important, which in turn helps explain long term involvement. Values change little in adulthood, and consequently are not especially helpful in helping us understand emergent, transforming commitments like blood donations.
Like Jim, I doubt that civic identities take the same form for everybody. I'm not so sure that factor analysis is the best way to identify the nature of civic identity, but I guess I'm open to the possibility.
To the extent that civic identity is associated with participation and a sense of membership in a society, I'm inclined to think we ought to value it and encourage kids to develop them. It's certainly true that there are limits to the psychological possibilities that can be realized in reality, but, if the average American kid is watching 3 hours of TV a day, I think there remains some psychological space for the acquisition of civic identity.
I'd think it quite surprising if elements of civic identity weren't context sensitive. One would imagine that one's connection to, and participation in, one's community and one's nation would vary according to the conditions in/characteristics of these social contexts.
As to the question of the relation to civic identity to ethical identity and political identity, I suppose it's a good question--presuming people have ethical identities. I'd think that there'd be some overlap, but it's an interesting question.