I think that due to the huge cast of characters in Haru and Tsukasa, I would see merchandise revolved around those characters, like little dolls and plushies of each character, and I could definitely see gashapon machines revolved around Tsukasa's many outfits, with the more elegant ones being rarer to collect. Come to think of it, Tsukasa himself could also be like a Barbie doll of sorts, with different outfits for him. I can also see image albums of the fictional band, "The Apple Lilies."
Basically, the possibilities are endless for this series.
