Audrey Landers was indeed a stunning guest star, although her character seemed a wee bit young for Starbuck, IMHO!
And as for other humans on the planet, I also reckon there are others hiding in the wild. After all, the way Spectre ran the place, if they never attacked the Cylon's, Spectre would just ingnore them and claim they are all dead!
But they could have made that point clear, for all we know that family are the only humans on the planet.
BRG