The fact that Harry is the 'Chosen One' would be a huge obstacle. His life is constantly in danger, and being in a relationship with him would put Tonks in harm's way too. Moreover, the wizarding public's perception could be a challenge. People might gossip about their relationship, and there could be a lot of pressure on them. For example, the media in the wizarding world might hound them, which could put a strain on their relationship.
One major challenge would be the age difference. Tonks is older than Harry, and this could lead to differences in their life experiences and maturity levels. For instance, Tonks might be ready for a more settled relationship, while Harry is still figuring out his place in the wizarding world. Also, their different social circles could pose a problem. Harry has his friends from Hogwarts like Ron and Hermione, and Tonks has her Auror colleagues. Their friends might not easily accept their relationship at first.
One major challenge would be the different cultural norms. In Westeros, women are often treated as second - class citizens, so a modern girl would have to fight against that. Also, the political intrigue is so complex that she'd need to learn fast to survive.
One challenge is making it fit within the established Harry Potter universe. Their relationship isn't part of the original canon, so the writer has to create a believable backstory. Another is dealing with the different personalities. Harry is often seen as a bit more naive in some ways, while Tonks is more experienced. Also, their age difference could be an issue to address in the story.
Another challenge would be his changed appearance. His fangs and pale complexion could make it difficult for him to blend in at Hogwarts. He might be ostracized by some students and even some teachers. His vampiric abilities, while useful in some ways, could also be a hindrance as he tries to maintain his normal wizard life. For instance, his sensitivity to sunlight could limit his outdoor activities during the day.
In a fanfic, Harry as a girl would face the challenge of re - defining her identity. She has been known as a male hero, and now she has to create a new image for herself. This could be difficult in the wizarding community where reputations are important. She would also have to adapt to the physical differences, like having a different body structure for dueling or flying on a broomstick, which could take time to get used to.
One challenge would be Harry's strong will. He has his own beliefs and values that are opposed to Bellatrix's dark ideology. Another challenge could be hiding Harry from Voldemort. Voldemort might not approve of Bellatrix raising Harry in her own way. Also, Bellatrix herself has a reputation to uphold among the Death Eaters, and raising Harry could be seen as a risky and strange move.
Perhaps Tonks' crush could be redirected towards her own self - growth. She realizes that her so - called crush on Harry is actually a sign that she needs to focus more on her own life and relationships. So she starts to work on her own identity and how she presents herself in the wizarding world. This way, the 'crush' is just a catalyst for her personal development rather than leading to a romantic relationship with Harry.
One major challenge would be the public perception. Snape has a rather dark reputation in the wizarding world, and Harry is a hero. People might not understand or accept their relationship, let alone them having a family. Their family could face discrimination or be the subject of rumors.
He might face the challenge of acceptance. The Snape family may be hesitant to welcome Harry, given Snape's complex relationship with him at Hogwarts. Also, there could be differences in magical practices. The Snape family might have their own unique ways of doing magic that Harry has to adapt to.
He'd face problems like getting the older students to respect him. After all, he's just an 11 - year - old kid.
One major challenge would be winning over the trust of the Slytherin students. They are used to a certain way of leadership and may be skeptical of Harry, especially since he was a Gryffindor. Also, there could be some traditional Slytherin families who oppose his leadership style as it may not align with their old - fashioned values.