I'm not 100% positive, but I think she's described her hair as almost-black, so probably a very dark brown. I'm not sure how that jives with the genetics, but since only her mother was Latina, I think it's possible.

The whole Edward thing was a little odd, I agree. Edward always struck me as, if nothing else, exceedingly professional. Step-parent ethics aside, it struck me as weird that he'd bring a child with him on a professional job. Especially a child who he's partially responsible for caring for.