https://www.youtube.com/watch?v=DI_clO3CbbU
Fuwamoco?
Koyori?

I feel like Haachama would want it to go to one of the new girls, and honestly, Gigi is popping up in my mind, I feel like she embodies the spirit
I feel like Shiori is also a candidate as well, but she might be too much of an introvert
Ririka maybe? La+? Kronii?

I can see an argument for Fauna, she'd honestly probably make use of it the best, but you can make the same argument for Watame.

Kanata?
She's evolved since the time her and coco lived together.