Another reaction could be confusion. Draco might not know how to feel. On one hand, he has his Slytherin pride and his clothes are part of that. But on the other hand, seeing Hermione in his clothes gives him a strange feeling in his stomach. He might end up being more curious about Hermione and her reasons for wearing his clothes.
Hermione might initially be shocked and afraid, but she would quickly gather her wits. She would assess Draco, trying to figure out if there was any way to sway him to her side. Given her ability to see the good in people, she might try to appeal to any sense of morality Draco has left, all while secretly planning her escape or a way to undermine Voldemort's plan of using her as a pawn against the good side.
Hermione might be shocked at first. She has always seen Draco as an adversary, so a neck kiss from him would be completely unexpected. She could push him away immediately and demand an explanation.
The other Gryffindors would likely be divided. Some would be outraged, thinking that Hermione has betrayed the house by getting involved with a Slytherin, especially Draco Malfoy. However, others might be more understanding and see that love can cross house boundaries. In Slytherin, Draco's friends would also have mixed reactions. Some would be proud that Draco has managed to get Hermione pregnant, seeing it as a sort of conquest, while others might worry about the implications for their standing in the wizarding world.
Draco would probably be extremely angry. He might feel a deep sense of hurt and betrayal, especially if he considered Harry a friend or at least an acquaintance he could trust. He could start plotting revenge against Harry, using his own cunning and Slytherin skills to make Harry's life difficult at Hogwarts.
Well, Draco could be very conflicted. On one hand, he has his own pride and his Slytherin upbringing which might tell him to stay away. But if he has developed deeper feelings for Hermione in the fanfic, he might put aside their past differences. He could start by using his family's resources to find a cure or at least better treatments for her cancer. He may also become more protective of her, keeping her away from those who might be unkind about her illness.
A great idea could be a time - travel fanfiction. Hermione accidentally travels back in time to Draco's childhood. She has to blend in, so she borrows some of his clothes. Draco, as a child, is curious about this strange girl in his clothes. This interaction could change the course of their future relationship in the original timeline.
Draco's friends from Slytherin would also be surprised. Some of the more traditional pure - blood families might disapprove, but others who have also changed their views after the war could be supportive. Pansy Parkinson, for example, might initially be jealous but then realize that Draco is truly in love with Hermione and could either become an obstacle or a helper in their relationship, depending on how she decides to handle her own feelings.
In a fanfiction with this theme, it could be set post - war. Draco and Hermione find themselves in a situation where they are on the run from some dark wizards who are after them for different reasons. During their escape, Hermione gets wet and cold. Draco, having a change of heart after the war, gives her his warm cloak. This act of kindness begins to break down the barriers between them, and they start to have deeper conversations, realizing they have more in common than they thought.
In the fanfiction, Harry wearing Draco's clothes can be a significant step in his character arc. It could represent his journey towards unity and breaking down the barriers between Gryffindor and Slytherin. As he puts on Draco's clothes, he's not just changing his appearance but also challenging the pre - conceived notions he had about Draco and the Slytherin house as a whole. This act could lead to him becoming more inclusive and open - minded, which are important aspects of his character development.
Hermione could also be very hurt. Her hair is part of her identity, and having Draco, who she already has a strained relationship with, do something so cruel would cut deep. She might go to her friends, Harry and Ron, for support. They would likely be just as angry as she is and plot some sort of revenge against Draco and his Slytherin friends.