You bring up a point, Kiara is one of the few in position to try and fill the gaps Coco will be leaving and I think there's potential in her to do so, altho I doubt as well. However, she doesn't have to, why I want her to try is that to fill Coco's shoes means grounding yourself into reality and considering the best approach to many things and I think that call to action and maturity may yet be the catalyst Kiara needs to grow up.
tl;dr Chicken could honestly try, She'll never truly fill the hole, but she has to realize that she doesn't need to, while still being able to help and instead take the time to mature.
Edit: That said, this can also backfire on her, but that's probably what would help her the most is that risk of backfire.