Okay so in the background of chapter 2 when they are walking under the sakura we can see Sumin-Ah and Sunj-ju sii (I don't remember well the names sorry) and guess what ? on chapter 5 page 26 of WDFS we can see Cho-ul and Ju-ah, meaning that the author had the idea of Pet's Aesthetics a long long time ago, such a bliss to discover that
I could only think of Frozen during the last chapter xD