By the way, about the debate, why is Nami older, but they are in the same class. They could well be *Irish* twins (this is when the mother gets pregnant when she is already pregnant). Taking into account the different seasons, they can start studying together. I know such siblings irl who studied together.
PS: There is also such a thing as hood twins.It is when the father gets 2 or more women pregnant within the same time frame,so the kids are almost twins. Considering William, this would explain the similarity between Nami and Summer in the past and Nami and Sasha in the present. They may actually have the same father, but different mothers.