One possibility is that they would try to find the origin of Voldemort's power in the past. They could search for the early Horcruxes or try to stop Voldemort from making them in the first place. Also, their presence in the past might cause some confusion among the wizards of that time. Some might think they are some kind of time - traveling wizards with strange powers. But overall, it would be a very exciting adventure full of unpredictable things.
In this kind of fanfiction, they might face various challenges while in hiding. For example, they could be constantly on the run from dark forces that are still after Harry. Maybe they have to find creative ways to conceal their identities, like using magic spells that are not commonly known. Also, their relationship could grow stronger as they rely only on each other in such a difficult situation.
Well, perhaps they will discover that magic has merged with Muggle technology in the future. Harry and Ginny could be amazed to find flying cars that are powered by both magic and electricity. They may also encounter new forms of dark magic that they have to fight against, or they might see a future where the wizarding world has achieved complete peace and harmony, and they play an important part in maintaining that peace.
In fanfiction, they might share a really special dance. Harry could be super nervous at first, but Ginny would make him feel at ease. They might also have some private moments away from the crowd, just talking and getting to know each other better.
They might enjoy a picnic by the beach. Ginny could be building sandcastles while Harry reads a book under a beach umbrella.
They might share some sweet and private moments. Maybe they have a cozy dinner together and talk about their future, like Ginny sharing her dreams of playing Quidditch professionally while Harry listens intently.
In some fanfictions, they might try to change certain events. For example, they could prevent the death of a loved one. Maybe they'd stop Voldemort from rising to power earlier, thus altering the whole wizarding world's history.
In the 'Harry and Ginny Christmas at the Burrow' fanfiction, there could be a lot of fun and magical moments. For example, Harry and Ginny could join the Weasley family in decorating the Burrow with twinkling lights and magical ornaments. They might also go on a little adventure in the snow -covered yard, perhaps encountering some friendly magical creatures. And of course, there would be the traditional Christmas carols sung around the fireplace, with Ginny and Harry holding hands and feeling the true spirit of Christmas.
There would be some humorous moments too. Harry might not be used to wearing Ginny's clothes and would fumble with the different styles. Ginny, in Harry's body, might accidentally use his more masculine way of speaking and shock her friends. Also, if they had to participate in Quidditch in each other's bodies, it would be quite a sight. Harry, in Ginny's body, would have to adjust to her style of playing, and Ginny, in Harry's body, would have to live up to his reputation on the broom.
In this fanfiction, perhaps Harry and Ginny would teach Teddy all about his parents. They might share stories of Remus and Tonks with him. Teddy could grow up in a loving environment filled with magic and family values.
They might start a family right away. In many fanfictions, Ginny would get pregnant soon after the wedding and they would experience the joys and challenges of preparing for a new baby.