I think their spirit Pokémon are as followed (not the ones pictured above): Anna and Arcanine, Hans and Zoroark, Kristoff and Sawsbuck, and Elsa with Weavile. Why? Arcanine is loyal like Anna. Zoroark is a shape-shifter, much like how Hans changed through the plot. Sawsbuck changes and Kristoff did, too. Weavile is Dark-and-Ice type and Elsa was first seen as a dark enemy, not pure like ice.