The emphasis on only bringing one person to the second screening tells me something drastic is coming between Hibari and Harema. Usually in these events, something goes wrong and the MC goes above and beyond for the girl, and her feelings deepen as a result. Maybe Hibari's outfit tears and Harema mends it while dropping a line like "Whatever it takes, I want to see you shine," and that would make her go doki doki. Or somehow her mom finds out and shows up demanding she withdraw, and Harema convinces her to let Hibari continue on the condition that winning means she can pursue Lolita fashion without interference. Hibari watching Harema defend her against her own mother would pull at her heartstrings.
Whatever happens, I hope it doesn't bleed into Harema's date with Amamiya. And honestly, since this isn't how the author writes, I doubt it will. Characters so far have respected their arrangements, and if they can't, they communicate in advance.
Hibari's the first of the "four beauties" being explored, and I expect the other two to follow after her arc wraps. I have a hard time believing the three beauties, including Hibari, will view Harema purely platonically, that he's just helping them overcome insecurities without any romantic stakes. Traditionally, that dynamic creates rivals who push the main girl to be more proactive for fear of losing him. But Amamiya doesn't need extrinsic motivation here. She's already deeply in love with Harema and actively moving toward dating him.
So I know where the author is going, but I also don't at the same time. The setup hints at competition, yet the foundation suggests no one's being played against each other.
Thanks for the translation!