Ideas (Prompts) for (Harmione, Harmony, Harry/Hermione)

What if Ginny is actually Harry's younger sister

Description of the idea
The application includes two potential plot development opportunities.
But the mandatory conditions are
1. The obligatory couple is Harry and Hermione.
2. No incest. Even if Ginny was in love with Harry, their relationship didn't work out.
3. No bad Potters
The background.
It is no coincidence that the Weasley family is known as blood traitors. The fact is that many years ago their ancestor made a spell that was supposed to ensure the birth of male heirs. However, everything did not go according to plan and the spell turned into a curse of the family, which excluded the possibility of the birth of girls. However, Molly has always dreamed of a daughter.
In 1980-1981, the Potters went into hiding. After Harry, James and Lily have another child, a red-haired girl (August 1981). No one knew about her existence (maybe only Sirius).
On the night of October 31, 1981, Dumbledore arrives at Godric's Hollow and discovers another child besides Harry. And here comes the problem. He knows that Harry is the child of prophecy, who must be protected with the help of blood charms, however, he understands that he will be able to persuade the Dursleys to take only one child, which should be Harry. What should I do with the girl? Then the idea arises in his head to give a red-haired girl to a red-haired family whose mother dreams of a daughter. The Weasley family did not know that this was the Potter child. Dumbledore said the girl's parents were killed by death eaters.
So Lily and James' daughter became Ginny Weasley. By the way, Ginny has Lilly's red hair, brown eyes and James's character, as well as his Quidditch hunting skills.
Options for fan fiction.
First, you can take the mandatory conditions + background, and then whatever your imagination desires.
The second one is more complicated. - Possible name: Daughters' time.
Here is an addition to the background. We all remember that Sirius was a rebel. He was also a school lovelace. But there was one girl he really loved. They had a whirlwind romance, with loud quarrels and passionate reconciliations. No matter how many girls Sirius had in his life, he loved one - Marlene MacKinnon. When Sirius proposed a plan that everyone would think he was a secret keeper, Marlin was furious. Since Voldemort will be hunting for the guardian, Sirius has hung a target on his back. Marlin tried to convince Sirius to hide too. But they failed and they had a big fight. Marlin (a Muggle-born witch) goes to her parents. Where she finds out that she is pregnant with Sirius's child. But the quarrel and resentment do not allow her to return to him. A girl was born. Nobody knows about the child. And one day, when the Marlin family gathers together, they are attacked by death eaters. Only Marlin's daughter was able to survive (the author of the application has a couple of ideas how this could happen). She is adopted by Marlene's relatives, whose only daughter (Marlene's cousin) was killed by death eaters. These relatives were Grangers.
After the battle at the Ministry of Magic - Sirius survived - the truth about who Hermione is is revealed (the author of the application has several possible options, as it became known).
However, around the same time, someone from the wizarding world recognizes two strangers as people who should be dead. (For example, Minerva brings a letter to a child, and recognizes James and Lily in her/his parents). The fact is that they do not remember the last 14-15 years of their lives.
And now James and Lily are faced with the task of fitting back into the magical world, becoming a part of the lives of their older children. But they were already living a safe life .Sirius, a man broken by Azkaban, is trying to become a good father to his daughter, who is quite freedom-loving and stubborn.
I would like to see the friendship between James and Sirius. Perhaps James' jealousy of Harry and Sirius' relationship. The development of a brother-younger sister relationship between Harry and Ginny.
Plus, let's not forget about romance. Definitely Harry/Hermione. Ginny would also like to find a decent match (in my opinion, the brave and courageous Neville would suit her perfectly). But apart from romance and the relationship of fathers and children, a war is coming. How will our heroes act? How will parents react if their children are in the midst of a war? We will learn from the fanfiction on this idea.