With the teachers, it would be quite a shift. Snape might have a different attitude towards Harry. Instead of being constantly critical, he could see Harry as a potential asset to Slytherin. McGonagall might be more watchful of Harry, worried that the Slytherin environment could lead him astray. As for his relationship with Neville, Neville might be a bit scared of Harry being in Slytherin at first. But later, they could bond over their shared experiences of being underestimated. Harry would also have new relationships with his Slytherin housemates. Some would befriend him, while others might be jealous of his fame.
His relationship with Ron would be very different. Ron might be initially distrustful or even hostile towards Harry in Slytherin. But as the story progresses, they could come to understand each other better. Harry's relationship with Hermione could also change. She might be more cautious around him at first, but then realize that Harry is still the same person deep down. And his relationship with Draco would be much more complex. They could start as rivals, but then become allies in some situations, as they both have a connection to Slytherin.
If Harry were in Slytherin, his relationship with Dumbledore would be one of the most interesting to explore. Dumbledore would likely be more guarded in his interactions with Harry. He would be constantly assessing whether Harry's Slytherin nature is leading him towards the light or the dark. Harry might feel a sense of betrayal from Dumbledore at times. His relationship with Ginny would also be different. Ginny might be attracted to Harry's new, more mysterious side as a Slytherin, but also be worried about the implications. And Harry's relationships with the Weasley family as a whole would be strained. They have a long - standing prejudice against Slytherin, and it would take time for them to accept Harry as part of that house.
His relationship with the teachers would also be different. Snape, for instance, might be more conflicted about Harry. On one hand, he's in Slytherin which Snape favors, but on the other hand, he's still Harry Potter. And Dumbledore would have to watch Harry from a different perspective, perhaps guiding him in a more subtle way to make sure he doesn't get too influenced by the darker aspects of Slytherin house.
His relationship with Hermione would likely change. Hermione is used to the human Harry, but now she has to deal with a phoenix - form Harry. She would probably be very curious and start researching immediately about any historical cases of humans turning into phoenixes. Ron, on the other hand, might be a bit more hesitant at first. He's used to the regular Harry and this new form might seem a bit strange to him. But overall, his friends would be protective of him. They would want to make sure that he is safe in this new form and not exploited by those who might want to use his phoenix powers for their own gain.
His relationship with Hermione would be very different. Hermione, who is an advocate for house - elf rights, would be in a strange position. She might try to help Harry break the spell, but also be conflicted about treating him like a normal house - elf. With Ron, Ron might not take Harry as seriously at first in his house - elf form, but then realize that it's still Harry and they need to work together. And with Snape, Snape would probably be even more dismissive of Harry as a house - elf, but Harry would still find ways to get under his skin.
With Dumbledore, it would be a complex relationship. Dumbledore would be cautious yet intrigued by Harry. He would want to guide Harry away from the potentially dark path that his Nathrezeim upbringing could lead him to. Harry, on the other hand, might be resentful of Dumbledore's interference at first.
His relationship with his enemies would change significantly. Voldemort or his Death Eaters might not recognize Harry as a rabbit at first, which could give Harry an advantage in some ways. However, if they did find out, they might see it as an opportunity to either capture or harm him more easily. Among his friends in Gryffindor, they would all be very concerned. Neville, for example, might try to use his knowledge of Herbology to find a way to reverse the transformation. And Ginny would be especially protective, seeing Harry in such a vulnerable state as a rabbit.
Some of the more traditional wizarding families, like the Malfoys, would likely oppose Harry's actions. They have always held a certain view of the goblins as being inferior. This would further widen the gap between Harry and those who uphold such old - fashioned and discriminatory views. However, among the younger generation of wizards who are more open - minded, Harry's actions could inspire them to re - evaluate their own views on the goblins, and he could gain new friends and supporters from this group.
His relationship with Dumbledore would likely be more complex. Dumbledore would need to guide Harry in understanding and controlling his dragon - influenced powers. Hermione might be both fascinated and a bit jealous of Harry's new - found abilities, but still be his loyal friend and help him research about his heritage.
Their relationship with Ron would be strained at first. Ron has a pre - conceived notion about Slytherin, so he might be suspicious of Harry and Hermione. But as time goes on, he realizes that they are still the same friends and they work together to bridge the gap between Gryffindor and Slytherin.
His relationship with Hermione and Ron would likely become strained at first. Since he's at a different school, they wouldn't be able to see each other as often. Hermione might be a bit jealous that Harry is experiencing a different magical education. With new friends at Beauxbatons, Harry could form a close bond with a French student who has a very different view on magic. This new friend could introduce Harry to new spells and ways of thinking that he hadn't considered before.
His relationship with Hermione would likely strengthen. She would be intrigued by his newfound heritage and would help him research more about Gryffindor. Ron, on the other hand, might feel a bit of envy at first but would soon get over it and be proud of Harry. With Dumbledore, Harry might have a more equal relationship as he is now the heir of one of the founders. Dumbledore could share more secrets with him. And with the Slytherins, they might view him with more respect or fear as he is the heir of Gryffindor, which could change the dynamic in the whole school.