Spolier: Who is who
So then Anna is Emma half sister and then Anna becomes Emma's grandma since Paris is Emma's missing dad and Anna is Paris's mother?
shareAnna and Ellie (not Emma) are step sisters, not half sisters - Anna is the daughter of Daniel (but not Celeste). Ellie is the daughter of Celeste and Paris.
And yes, Anna is Ellie's grandmother because she turns out to be Paris' mother and Paris is Ellie's father.