I've also read 'Green and Red: A Slytherin - Gryffindor Love Story'. Here, Ginny is initially skeptical of Harry being in Slytherin. But as the story progresses, they discover they have more in common than they thought. The fanfic delves into their personal growth, their love for Quidditch which becomes a connection point, and how they overcome the house rivalries to be together.
One plot twist could be that there's a prophecy about a Slytherin and a Gryffindor uniting the wizarding world, which is revealed to be about Harry and Ginny. This forces them to deal with a lot of attention and expectations from the wizarding community. It also makes their relationship a focal point of a much bigger plot, with dark forces trying to stop them from fulfilling the prophecy.
Well, at first, most of Harry's Gryffindor friends would be taken aback. They have always had a certain animosity towards Slytherin. But as time goes on, if they see that the Slytherin Harry is betrothed to is kind - hearted and doesn't hold the same prejudices as some of the other Slytherins, they might start to come around. For instance, Seamus might start to joke around with the Slytherin, and Dean could start to include them in group activities. It would be a slow process of acceptance as they get to know the Slytherin better through Harry.
Ginny could first be in shock. But then, she would start thinking of ways to help Harry. She could offer him emotional support, like being there for him when he is feeling down about being expelled. She may also try to rally their mutual friends to support Harry, whether it's by protesting the decision or by helping him find a new place to belong in the school.
A fanfiction in this vein could show Ginny using her Slytherin traits to her advantage in the wizarding world. Maybe she becomes a master at potions, a subject often associated with Slytherin. She could also form unexpected alliances within Slytherin and change the perception of Gryffindors within that house.
Well, they could become quite the power couple in Slytherin in fanfiction. Harry's natural leadership skills and Ginny's fierce determination would fit well in Slytherin's ambitious atmosphere. They might have to deal with the prejudices within Slytherin towards those with different backgrounds, especially Harry being a so - called 'half - blood'. But they could also rise above it. Harry could use his fame in a different way in Slytherin, perhaps to gain more influence and change the house from within. Ginny could befriend some of the more progressive Slytherin girls and start to shift the traditional Slytherin views on gender roles as well.
The novelty. In the original series, Ginny is in Gryffindor. Fanfiction that puts her in Slytherin turns the whole story on its head. It allows for new relationships and character interactions. For example, Ginny might have to deal with Slytherin stereotypes while still being with Harry, who is the hero of Gryffindor. This creates a lot of drama and tension.
If Harry was kicked out of Gryffindor in Ginny - related fanfiction, Ginny would likely be one of the first to oppose the decision. She might secretly help Harry by providing him with a place to stay in Gryffindor's common room undetected. And she could start her own investigation into what really happened, suspecting foul play. After all, Harry has been a hero in Gryffindor and Ginny wouldn't let him be cast out so easily.
In these fanfictions, Ginny being the heir often makes their relationship more equal. Harry is used to being the 'chosen one', but Ginny having this special status gives her more agency. It deepens their bond as they face new threats and challenges together related to Ginny's new role.
Well, if Harry and Ginny went to Slytherin, it would completely turn the story on its head. Harry has always been seen as a Gryffindor, and Ginny too has those Gryffindor traits. In Slytherin, they'd face a lot of prejudice from their housemates at first. Slytherins are known for their ambition and cunning, and Harry and Ginny would have to adapt. Harry might use his skills to outwit the more negative Slytherin elements. Ginny could also bring a different kind of courage to Slytherin, not the typical Gryffindor bravado but a more nuanced form of standing up for what's right within the Slytherin house environment.