Let's break it down option by option:>Uruka
She'd be quite reluctant to pick him up or even interact with him due to her nature. She's also very tense due to her knowing about the fireworks rumor. She would like to but she'd easily chicken out>Fumino
Also aware of the fireworks rumor so she'd be hesitant. She was chewing out the ibara club when he was down on his ass so it'd be difficult to make it fit her. >Asumi
She's aware of the rumor, of course, but she's holding onto a book and a bowl of udon before so it's unlikely that it would be her>Rizu
Likewise with Asumi, she's holding onto something so it's just as unlikely that it's her, but if we remove that option it could just as well be considering her autism>Sensei
She's not aware of the rumor because she was never one for such trivial high school things. She wouldn't hesitate to pick him up because he's her student. Also, the wording for Nariyuki's statement "Bound together... me... it can't be... right?" He can still imagine being together with any of his friends because it's in the same age group. "It can't be" with sensei because of the age difference and the teacher-student relationship. Also if you look closely fireworks girl is wearing something with long sleeves.