What is KC’s “Before everything changes” is the same event that pushes Alice to become Claire
For all you anti- Alice/claire people, just be kind.
But what if the one big hiccup everyone has of “but Alice would leave everyone behind” can be explained by whatever big change KC hinted to?
It would be in about 16 years which would put Alice around Nick’s current age and maybe she jumped and either can’t go back or it isn’t safe to or some other explanation.