There's also a possibility that she could inherit a certain level of resistance to the moon - related magic, considering Remus' werewolf condition. It doesn't mean she would become a werewolf, but she might be less affected by lunar - influenced spells or curses. This could give her an edge in certain magical battles or challenges that are related to the moon's magic.
Hermione might inherit some of Remus' occlumency or legilimency skills. Remus was a smart wizard and being able to protect one's mind is a valuable skill. If Hermione had this, it could enhance her ability to keep secrets and also to detect when others are trying to deceive her. This could be very useful during her time at Hogwarts, especially when dealing with the likes of Voldemort and his followers.
Hermione could become more attuned to the darker aspects of magic. With Remus being a werewolf and Sirius having his own dark family history, she might explore the gray areas of magic more. For example, she could study more about the dark arts not to practice them, but to understand how to better defend against them. This would be a significant shift from her canon character who mostly stuck to the 'light' side of magic study.
She could inherit Hermione's gift for spell - casting. Hermione was known for her precise and powerful spells, and their daughter might be able to perform complex spells with ease from a young age. For example, she could be excellent at transfiguration, like turning a teacup into a mouse flawlessly.
If Hermione was Remus's twin sister in fanfiction, their combined magical abilities could be really powerful. Hermione is already very intelligent and skilled in magic, and Remus is a powerful wizard too. Maybe they could combine their knowledge of spells and magic theory to create new spells or ways to combat dark magic.
They could develop a shared form of telepathy. Since they're twins, it's not far - fetched to think they could communicate without words. Maybe they could combine their magic to create a new kind of protective shield that's stronger than any single spell. Another ability could be the ability to sense each other's emotions more acutely, which could then be harnessed to boost their magic when they're in danger or facing a difficult task.
There are some really interesting fanfictions on this concept. One I remember had Hermione growing up with a unique blend of Remus' calm wisdom and Sirius' rebellious spirit. It was fascinating to see how she navigated Hogwarts with that background.
A new storyline might involve Hermione exploring the secrets of her fathers. She could learn about Sirius' family secrets and Remus' experiences as a werewolf in a more personal way. This could lead to her finding new ways to fight against dark magic, as she combines the Gryffindor courage from Sirius and the Ravenclaw wisdom from Remus. It could also create a lot of drama as she tries to balance her old life with this new revelation of her parentage.
It's possible that their children could inherit Hermione's gift for languages. She was able to learn and master many magical languages during her time at Hogwarts. Along with that, Draco's family's talent for flying could be passed on. So, their children might be excellent at flying on broomsticks and also be able to communicate with magical creatures in different languages. Moreover, they could inherit a combination of their parents' defensive magic skills. Draco was trained in some forms of pure - blood defensive magic, and Hermione was always good at using magic for self - defense. Their children could develop a unique style of defensive magic that combines both of these aspects.
In the realm of fanfiction, the idea of Hermione being Sirius and Remus' daughter might stem from a desire to explore different family dynamics. It could start with a time - traveling incident where the past is altered. Sirius and Remus might have found a way to ensure Hermione's existence in a different timeline. This would completely change the relationships in the Harry Potter universe and open up new storylines for the author to explore, like how Hermione would grow up with two very different fathers, one a werewolf and the other an escaped convict in the eyes of the wizarding world.
Well, in a fanfiction, anything can be made possible. Maybe it could be through some sort of magic gone awry. For example, a spell that was meant to protect Hermione's real parents ended up warping reality and making her seem like Remus and Sirius' daughter. Another idea could be that some dark wizard had a plan to manipulate their genes or magical essence in some way to create this new family connection.
In terms of her relationship with Draco, it could take an unexpected turn. With Remus as her father, she might be more empathetic towards Draco's family situation, considering the Malfoys' views on werewolves. This could lead to a more complex relationship between them, rather than just the typical rivalry. It could also change how she views Snape, knowing that Snape had a complex relationship with her 'father' Remus.