Well, Harry Potter being immortal means he has a vast amount of knowledge and experience. He could become an advisor to the Federation. He might use his magic to enhance the technology of the Star Trek world. For instance, his ability to apparate could inspire the development of new forms of transportation in the Federation.
He could be a powerful being that the Star Trek crew encounters. Maybe he's been traveling through different dimensions and ends up in the Star Trek universe. His magic would be something completely new and strange to them.
The concept of an immortal child in Harry Potter fanfiction is quite fascinating. Since the wizarding world already has so many magical elements, an immortal child can be a catalyst for various plot developments. For instance, they could be a key to unlocking some long - forgotten magic or they might have witnessed historical events that are relevant to the current state of the wizarding world. They also present interesting relationship dynamics, as they would outlive most characters and have to deal with the loneliness that comes with immortality.
In a fanfiction of this kind, we might see the Hogwarts houses incorporated into Star Trek. The Sorting Hat could be brought into the Star Trek universe and sort the crew members. Spock might be a Ravenclaw for his intelligence, while Kirk could be a Gryffindor. Also, the idea of the Deathly Hallows in the Star Trek world is fascinating. The Elder Wand could be a powerful weapon against the Klingons or other enemies.
Hawkgirl could be a new kind of magical creature. Her ability to fly with her wings would be a unique form of magic in the wizarding world. She might be a protector of some hidden magical place in Hogwarts or the Forbidden Forest, like a guardian of an ancient magic that Voldemort is after.
In fanfiction, umbramancy can fit in by being a long - lost or forgotten magic. It could be something that was once used by ancient wizards but lost over time. For example, it might be rediscovered in the Forbidden Forest by a curious student.
Shukaku could be a powerful magical beast that has been sleeping deep within the grounds of Hogwarts for centuries. Only a very powerful spell or a unique combination of spells could awaken it. Once awakened, it could either be a great ally or a terrifying foe depending on how the wizarding community treats it.
Supergirl could be a foreign exchange student of sorts in the Harry Potter universe. She could be there to study magic while also sharing her own Kryptonian knowledge. Her superpowers would make her stand out, but she would also have to learn the rules of the wizarding world, like not using her powers when it's against the wizarding code.
He could fit in as a unique hero. His magic could be seen as a special power like the others in DC. For instance, he could use his Patronus charm to fight off fear - inducing villains.
Illumi can fit in as an outsider with unique skills. His combat and stealth abilities are not like anything in the wizarding world, so he could be a wildcard. For instance, in some fanfictions, he might be seen as a new kind of threat or an unexpected ally to the Order of the Phoenix.
Freerunning can fit into the Harry Potter universe by adding a new dimension to movement. For example, it can be used for escaping from dark wizards in the narrow alleys of Diagon Alley or Hogsmeade. The characters can use their parkour skills to quickly jump over obstacles and get to safety.
She could be a powerful ally. Since Bella has enhanced physical abilities in her own story, in the Harry Potter universe, she could use those to help in battles. For instance, she could be part of the Order of the Phoenix and use her speed and strength to fight against Voldemort's forces.