I'm not sure specifically about 'Naruto and Sakura Matou lemon fanfiction' as 'Matou' is from a different series (Fate/stay night) and mixing it like this might be a very niche or even non - existent concept in a proper fanfiction context. There could be some very strange crossovers out there, but it's not a common or widely - known combination.
Since this is a very odd combination, it's hard to say exactly. But perhaps it would involve some sort of strange crossover where the worlds of Naruto and Fate/stay night collide, and Naruto and Sakura get involved in a situation related to the Matou family in a romantic or sexually - tinged way, though this is really stretching the boundaries of normal fanfiction concepts.
Harry's magic is mainly based on incantations and the use of a wand. Sakura's magic, especially as Dark Sakura, is more instinctual and connected to her very being. Their powers could interact in a way that Harry's spells could act as a sort of catalyst for Sakura's power. For example, if Harry casts a spell of protection around them, it could enhance Sakura's ability to focus her dark magic without it going out of control.
Another plot could involve a magical tournament that somehow brings Harry Potter and Dark Sakura Matou together. They are forced to compete against each other at first but then realize that there is a greater conspiracy behind the tournament. They then join forces, with Sakura's dark magic and Harry's quick thinking and diverse spellcasting abilities becoming a formidable combination to uncover the truth and defeat the real villains behind the scenes.
Sure. In fanfiction, the relationship between Sakura and Naruto can be played around with a lot. Sakura's admiration for Naruto can be shown more prominently, making her seem like a fangirl. For example, she might be written to always be in awe of Naruto's new jutsu or his heroic deeds more than in the official story. It gives writers a chance to delve deeper into her feelings for Naruto in a different light.
Yes, there are likely to be such fanfictions. In the Naruto series, Sakura can be quite assertive and strong - willed. Her temper and skills could potentially be a source of intimidation for Naruto in the creative interpretations of fanfiction writers.
It could be Sasuke. If Sasuke has some sort of newfound connection with Naruto and it causes Naruto to shift his focus away from Sakura, then Sasuke would be the cause. For example, if Sasuke and Naruto team up for a powerful mission and their bond deepens in a way that makes Naruto neglect his relationship with Sakura.
One possible reason could be for the sake of creating a more complex love triangle in fanfiction. Maybe the writer wants to explore a different dynamic where Naruto and Hinata's relationship is strengthened by having a common dislike for Sakura. It could also be that the fanfiction writer is trying to give Hinata more agency and make her a stronger character by having her oppose Sakura in some way, perhaps in matters related to Naruto's affections.
One interesting storyline could be Sakura joining the Anbu and having to prove herself among the male - dominated group. She might face challenges like secrecy requirements and intense training, all while Naruto is on his own journey, and their paths cross in unexpected ways during missions.
On Naruto's side, he would probably feel guilty after realizing what he had done. This guilt could make him try to make amends, but Sakura's initial reaction of anger and hurt would still be a big obstacle in their relationship. Their interactions would be filled with tension and awkwardness.