LCPE-ND is passion behind a defensive stance
Tsundere Yankee contributes pride, loyalty, and an awkward way of exposing tenderness. Enchanting adds present-focused emotion and rapid action, making this the sibling most likely to follow a strong feeling before a careful plan exists.
They are not indifferent and then suddenly interested; both the toughness and sweetness can be active at once. The visible switch depends on whether the person feels safe enough to stop guarding what is already intense inside.