Hagrid would be a likely helper. He has a great knowledge of magical creatures and would surely know a lot about phoenix eggs. He could give Harry advice on how to take care of it.
Dumbledore could be another important figure. He's wise and experienced. He might have some ancient knowledge about phoenix eggs. He could guide Harry on the significance of finding the egg and what it could mean for the future of the wizarding world. Also, other magical creatures in the Forbidden Forest might unknowingly help Harry. For example, the centaurs might give some cryptic advice that turns out to be useful in the end.
His best friends Hermione and Ron would surely be there to help. Hermione with her vast knowledge of magic could research about the egg, and Ron with his loyalty would stand by Harry's side in any danger related to the egg.
Dumbledore could also be involved. He's extremely knowledgeable and powerful. He might have some secret knowledge about basilisk eggs. He could guide Harry on whether to keep the egg or destroy it, depending on the greater good of the wizarding world.
Hermione would most likely help. She's always been there for Harry, and with her vast knowledge from books, she could offer a great deal of advice on how to take care of the dragon egg. Ron might also be involved. Despite his initial fear of things, he has a brave heart and would probably stand by Harry's side.
In the 'Harry Potter finds a phoenix egg fanfiction', it could be that the egg has some sort of special power or mark on it. Harry could find himself in a race against time to protect the egg from dark wizards who want to use it for evil. He might also have to figure out the proper way to care for a phoenix egg, which could involve consulting old books in the library or asking Hagrid for advice.
His friends from Hogwarts, like Ron and Hermione, are likely to help. Ron could bring his family's practical knowledge of wizarding homes and Hermione would contribute with her extensive research skills.
Hermione would be a great help. Her vast knowledge of magic and books could provide the necessary information for building the planet, like the right spells and magical theories.
Dumbledore might also play a role. He has vast knowledge and experience. He could offer some wise advice or even provide a special magical item or spell that is crucial for the unicorn's healing.
Dumbledore might offer some guidance. He has vast knowledge and experience. He could tell Harry about the significance of different elements in a staff and how to combine them to make a truly powerful and unique magical tool.
Dumbledore might help in a spiritual or advisory way. Even though he's passed away, his wisdom could be passed on through memories or some magical means. Also, Hagrid could be a great help. He could assist in building areas suitable for magical creatures with his love and understanding of them.
It's possible that an old acquaintance from Hogwarts who has family ties in America could assist him. This person might already have a network in America and could introduce Harry to important people. Also, there could be some reclusive magical scholars in America who, out of curiosity about Harry's powers and his role in the UK, decide to help him. They could teach him new magical skills that are specific to the American wizarding world.