If Voldemort loses his memory, Harry might initially be extremely suspicious. But as he sees Voldemort's new, innocent state, he could start to feel a bit of pity. He might still be on guard, but not as hostile as before.
If Snape loses his memory, initially Harry might be very confused. He's used to Snape being his enemy. But without his memories, Snape might not show the same animosity towards Harry. Harry could even feel a sense of pity and try to help Snape regain his memories. Their relationship could shift from one of hatred to a more complex one of trying to understand and help each other.
The relationship would become extremely complex. Harry would be confused and conflicted. He's been taught all his life that Voldemort is pure evil, but now he's been saved by him. Voldemort, on the other hand, might start to see Harry in a different light, perhaps as a tool or as someone with whom he can form an unusual bond. It would be a relationship full of mistrust on Harry's part and manipulative intentions on Voldemort's.
The relationship would become extremely complex. Harry would no longer be able to simply see Voldemort as pure evil. He would be in a state of confusion and moral dilemma. Voldemort, on the other hand, might start to view Harry as a more interesting pawn rather than just an enemy to be killed. They could develop a strange sort of respect for each other, at least on a surface level.
His relationship with Voldemort could change significantly. Voldemort might not immediately perceive Harry as a threat if he looks like a girl. He has a certain image of the boy who will be his downfall, and a girl - like Harry would disrupt that. This could give Harry an opportunity to get closer to Voldemort, perhaps infiltrate his ranks in a way that he couldn't as a boy.
At first, it would be extremely tense. Voldemort would be highly suspicious of Harry's motives. Harry, on the other hand, would be very cautious as he is approaching his mortal enemy. But as they start to interact more, there might be a grudging respect that develops if they find they have common goals.
Another plot could involve Voldemort's memory loss causing a power vacuum in the Death Eater ranks. His followers might start to fight among themselves to take over his position. Meanwhile, Voldemort, now named something else perhaps, could be living a simple life in a small wizarding village. He might start to show magical abilities that are different from his previous dark magic, like a natural affinity for healing spells. Harry and his friends would then have to decide whether to expose him or protect him from those who might want to use him for their own evil purposes.
At first, Dumbledore might see Harry as an even greater threat. But as he delves deeper, he could realize that Harry has the potential to be a powerful force for good, despite his dark lineage. So, Dumbledore would start to mentor Harry in a different way, focusing more on helping him come to terms with his identity and use it for positive change.
Well, in such a fanfiction, Harry being Voldemort's snake might initially make their relationship more of a master - servant one. But as the story progresses, Harry could start to resist Voldemort's control, leading to a more adversarial relationship.
The relationship might turn into one where Harry has to constantly remind Dumbledore of who he is and their shared experiences. Dumbledore, in his senile state, could forget important things about Harry like his role in the fight against Voldemort. Harry would then have to patiently re - introduce himself and the situation. This could be frustrating for Harry at times, but it could also deepen his understanding of Dumbledore as a more human and fallible figure.
In such a fanfiction, Voldemort would view Harry as his possession. He'd order Harry around, thinking he can use Harry's wolf - like abilities for his own dark deeds. However, Harry would not go down without a fight. He'd constantly be trying to undermine Voldemort from within. Their relationship would be a very strange and twisted one. Harry would have to pretend to be loyal while actually hating Voldemort with every fiber of his being. And Voldemort, being so arrogant, might not realize how much of a threat Harry still is even in his wolf form until it's too late.