The count of story missions in Hogwarts Legacy is hard to pin down exactly. Roughly, there are about 30, but it could be more or less depending on your gameplay style and exploration of the game world.
I think there are around 30 main story missions in Hogwarts Legacy. But it might vary depending on how you play and if you count some side quests as part of the main story.
The number of main story quests in Hogwarts Legacy isn't set in stone. It depends on your choices and progress. Roughly, there could be about 25 main quests or so.
If there was a rivalry before Hogwarts, it could carry over and make their interactions at Hogwarts more tense. However, this could also lead to them pushing each other to be better. For example, in Quidditch, if Fleur is also a good flyer, Harry might strive to outperform her, which could improve his skills as a Seeker. And over time, this rivalry might turn into mutual respect.
Their meeting could also mean that Fleur might be more protective of Harry at Hogwarts. Since she knew him before, she might feel a sense of responsibility. So, during the Tournament, she could offer him some tips or help in a more discreet way, which could change the dynamics of how the Tournament unfolds for Harry.
If they meet before Hogwarts, they might already have a sense of loyalty towards each other. So when they get to Hogwarts, they could look out for one another. For example, in a dangerous situation like a run - in with a rogue magical creature, they would be more likely to help each other compared to if they were just acquaintances. This pre - Hogwarts meeting could also mean they have inside jokes or shared memories that make their Hogwarts years more enjoyable.