Your playthrough is canon whether you rename the relationships or not. Here and there, there are little tweaks in the dialogue to support the step children relationship or the blood kin relationship, depending on your choice. In places, a bit of your own mental arithmetic is required to fill potential gaps. In one case they're supposed to be Children of Zeta assigned to the mc, in the other they're actually hiw blood. Either way, what matters to the characters are the personal bonds. In every way that matters he is their father and they are his daughters. As they say, the parents are those who raise them, whether they sired them or not.