Loki in Harry's head would be a disaster for his relationships. First of all, Harry's relationship with his friends would be strained. Loki might plant thoughts in Harry's head that make him suspicious of his friends' motives. For instance, he could make Harry think that Ron is jealous of his fame again, which could lead to arguments. With Hermione, Loki could make Harry resist her advice, thinking it's too controlling. And in terms of his romantic relationships, like with Ginny, Loki could make Harry act cold or overly flirtatious in inappropriate ways, causing Ginny to question Harry's feelings for her.
His relationships would likely be in turmoil. His friends might notice a change in Harry and be confused. Loki could make Harry act distant or say strange things to Ron and Hermione, causing them to worry. And his relationship with Ginny might also be affected as Loki might make Harry act in ways that Ginny doesn't understand.
Loki's mischievous personality could make Harry more adventurous. Harry might start to take more risks in his magical studies and in facing Voldemort. For example, he could be more willing to try out untested spells or strategies.
If Loki were in Harry Potter's head in fanfiction, it could lead to some interesting power dynamics. Loki has his own set of magical abilities from the Norse mythology realm. He could potentially influence Harry's use of magic. For example, he might show Harry some new ways of using spells that are more devious or creative. However, he could also put Harry in danger by leading him into situations that seem okay at first but are actually traps set by Loki's enemies or just his own amusement.
His presence could make Harry more protective. Harry might be more cautious in his adventures, not wanting to put his little brother in danger. For example, when dealing with the Marauder's Map, he might be more hesitant to use it if he thinks it could expose his brother to trouble. Also, his friends like Ron and Hermione would have to adjust to having a younger, perhaps more inexperienced, person around. They might feel responsible for him as well.
If he transfers, his relationships with his Hogwarts friends would be greatly affected. Hermione and Ron might feel betrayed or worried about him. They might try to convince him to come back. His relationships with his teachers would also change. Some teachers might be sad to see him go, while others might think it's for the best.
The dragon's presence could have a significant impact on Hogwarts. For starters, it would change the security measures. The school would need to figure out how to keep the dragon safe and also protect the students from it. There might be new spells and enchantments put in place. Also, the dragon could become a part of some classes, like Care of Magical Creatures. Students would learn about its unique abilities and behaviors.
Well, it would probably strengthen his relationship with his friends. His friends would be happy for him to have his parents back, and it could lead to more group activities like family - style outings. For instance, they might all go on picnics together with Harry's parents.
In fanfiction, Naruto joining Team 10 would create some interesting relationship changes. Naruto is a bit of a loner at first in the original story, but in Team 10, he could be the glue that holds them together. He has a way of making people feel important. For Ino, Naruto could be a source of inspiration in terms of becoming stronger. His presence would also add more competition among the team members, which could either strengthen or strain their relationships depending on how they handle it.
If Loki were to enter the Harry Potter world, it could significantly disrupt the plot. His ability to deceive and manipulate could lead to many characters making wrong decisions. For instance, he could trick Dumbledore into believing a false prophecy, which would send Harry and his friends on a wild goose chase.
Hermione would probably be both fascinated and a bit exasperated. Fascinated because Tigger is such an unusual creature, but exasperated because his bouncy antics might disrupt her study time. Ron would likely be amused at first, thinking Tigger is a great source of entertainment. He might try to get Tigger to do tricks for him. Harry, on the other hand, would be more cautious. He would see Tigger as a potential ally or a new responsibility. He would want to make sure Tigger doesn't get into too much trouble or put himself in danger in the wizarding world.
Dumbledore would be very cautious. He would likely sense the great evil in Palpatine immediately. He would start to research and try to find a way to neutralize the threat. Hermione would be intrigued and start reading every book she could find about this strange new figure. Harry, on the other hand, would be more instinctive. He would feel the danger and be ready to fight if necessary.