I could kind of see the ukulele as Callie's instrument of choice.

[LoudyKing101]

I mean, think about it. She's a high-spirited, energetic pop idol. She would most likely play the ukulele in her spare team.
Surprised there isn't any fan art of this, actually.

 

[LoudyKing101]

What do you guys think?

 

[Agent_1000008]

That does make sense, it seems to fit her personality. Being an energetic person, the ukulele would suite her quite well

 

[Overvo1d]

I think she would play a cool instrument