Funfact: Qingxiao's showcase is set before Buling had become a Black Shores member; also Qingxiao has been mentioned in Buling's backstory texts, and I think it'a very cool
In a few shots it's made clear that she's missing her noise/reverberations-cancelling headphones. They were specially designed and produced for her by Huaxu Academy after she started her wanderings and stayed around Jinzhou for a while
She has been travelling for a surprisingly long time in fact, even if the timeline isn't very specific
And yes, even her match against Jianxin and Qingxiao noticing her, albeit she was not refered to by name, are mentioned in the menus, although it's depicted in a slightly different manner.
In any case, I find such little interactions and teasings about possible characters extremely cool, and I hope Kuro continues adding that. It makes the world so much more lively and interconnected despite the nations borders