Throwing two cents in (cause I only have that much on me right now) regarding backstory.
I think compromise is probably the only sensible way to deal with things at this rate (2/2 split vote with 3 votes uncast) so unless everyone votes, I suggest the following:
Biological family, but not all of them. Some of them are already biologically - related angels (probably the heads of family so we can throw incest jokes at them so that it makes more sense that they gather the other virtues) but they were chosen just the same. Doing so would open up the following options:
-Non - human, non - angel virtues (if the angels were chosen just like the humans, then it makes sense that the choice pool extends beyond the human / angel species as a sort of equal opportunity thing)
-Differing backstories
-Explanation of inevitable plot hole of familial differences
As for why I chose to vote for non - biological family, it's simple: there's more options to make the characters individuals outside the family than if they were biological. Family influences a lot of character stuff, and if they all come from one big interrelated family with banjo noises then there's going to be a lot of necessary overlap. Personally, I prefer that my character be as individual as possible even if she's still defined by her family.
Also, @"hyperhurricane" cubaos in agreement