Aside from saving the child who becomes her great? grandmother? Aurora*, is the Latin word for dawn, and the goddess of dawn in Roman mythology and Latin poetry. Interestingly, in some versions of myth, she’s the daughter of Hyperion (Isn't this the hotel Angel has?). She has two siblings, a brother (Sol, the sun) and a sister (Luna, the moon). This feeds my theories about Twilight.
Spike speaks Latin (he tells us this) so he'd know this. - it's piggy=backing on the love he shows for Dawn in the series. The implication being that not only does Buffy save her own father (the patriarchal past that will/has done so much damage) but she also saves that thing she will die for (thus enabling the resurrection in 6 - providing the basis for the emergence of the relationship between them). However, we know the complexity of Dawn's real and symbolic relationship to Buffy (that she's Buffy as a child, an unsullied part of Buffy etc) so this also feeds into the symbolism of the baby. In addition, I'm wondering it there's a crossover with A5 where Spike saves Junior?
I think in part (a very large part), it's about cultural representation and frameworks of understanding. The implicit and explicit reference to film and cinema-going suggest that movies play a big part in structuring people's relationship with the world (confirmed by John Baxter who describes Spike and his army as "monsters from his comic books, demons from Saturday morning flicks"). It's telling that Spike mentions Westerns as his favourite form. This is pre-The Searchers - Ford's valediction to the Western (it's telling from the vampire perspective that thresholds are so important in The Searchers). The point I'm making is most of the Westerns he's seen will emphasis difference - they'll have a clear cut us/them white hat/black hat mentality - there's no blurring of boundaries. It's interesting that Spike is the one who is emphatic about difference - as illustrated by his use of national stereotypes.
I was going to write more but I've forgotten the plot and I haven't got time to re-read. My opinion? It's dead clever this! I love what she does with the poem!