That child doesn't look like any African blooded albino I've seen...but the pics I've seen aren't good enough to be sure.
But with a mixed blooded family like that, it's not unusual that a kid would pop who was lighter skinned...the unusual thing is that it's in a twin set.
African albinos are more common than European albinos so someone with partial African ancestry is more likely to carry it. I agree that someone with mixed ancestry can produce throwbacks in every direction but I would expect most traits to be inherited in groups. The fact that this little girl looks so much like her sister (except for pigment) makes me suspect a more unusual inheritance pattern at work.