I feel like it's been a very long time since we've seen him actually work his Hikari job. I feel like him being forced into a mini fashion show is a way to make up for her absence :3 Welcome back Hikari!
I mean... why can't both Amamiya and Harema try convincing her? Why does it have to be purely Harema?? Especially if Amamiya can sympathize with it, then she also can have a say to convincing Hibari or her mom.