Vivienne is always quick to give Evelyn a hug or offer her a toy or feed her or direct her away from danger (or just direct her away from rooms that she doesn't want her to go into - I think she enjoys having someone smaller than her around). The moments of sibling rivalry between these two are few and far between. They may look like they came from different tribes, but these two are definitely sisters through and through.
And I love the way Evelyn wrinkles her nose when she smiles. I hope she keeps that forever.