The hell, there was no kuyashii expression at all when she sang everything, even the higher harmony o.o Well, they do say singing is a natural action and its not something you force out of you, you have to do it without any tension to your muscles or body for that matter and keep yourself relaxed, and she did exactly that. She also doesnt sound as nasal as the other two, and she didnt have a screamish voice either. Just...total package looks, singing, dancing, and personality probably (I dont see much oc her interactions with others but I've read somewhere that she's goofy and clumsy(?), which sounds so cute

)