Well, Bakugo might scoff at first. He'd probably think Batman is too brooding and not as straightforward as he likes his heroes. But then as he reads more of the fanfiction, he might grudgingly admit that Batman's detective skills are cool. Deku, on the other hand, would be super interested. He'd be analyzing every move Batman makes in the fanfiction, taking notes in his head about Batman's strategies and how they could be applied in his own hero work. Uraraka would be more focused on the relationships in the fanfiction. She'd be all 'aww' at the cute moments and feel for the characters when they're in trouble.
Sure thing. Denki and Iwabe are nowhere to be found in the manga. It seems the creators chose not to incorporate them into the original manga storyline.
Denki Kaminari remains alive throughout the manga. The author didn't include his death as part of the narrative. His character has continued to play an active role in the story without facing such a fate.