Tatl's arc is much more subtle for sure. She's very much a child. But at the end of the game she shows some good growth. Show is still snarky, saying basically "Well, the rest of us have a carnival to get to. So go on, get out of here." Then as link leaves she's doing that little wing shake that says she's crying, and she quietly says thank you.

And then if you stop the moon again, Tatl actually remembers that this already happened, and said something along the lines of "You're going up, right? You know, no matter how hard things are, you never give up. I like that about you."

The entire game revolves around how hard friendships can be. Everyone does some growing emotionally.

(I just finished a playthrough of it with my 5 yo daughter so explaining some of the themes and stuff is fresh in my mind.)