They could be like brothers. Harry has a strong connection with the Weasley family already, and with Bill and Charlie, it could be a natural extension of that. They might look out for each other and support one another in any difficult situation.
They could help Harry by teaching him new spells. Bill might teach him some advanced defensive spells he learned as a curse - breaker. Charlie could show Harry some unique ways to use magic around magical creatures. Hermione would of course be there to ensure Harry studies hard and understands the theory behind the spells.
In a fanfiction scenario, perhaps Hermione has a research project and enlists the help of Bill, Charlie, and Harry. Bill could offer insights from his travels, Charlie might contribute with his expertise on dragons as it relates to the research, and Harry would be there for moral support and to offer his unique perspective as the Boy Who Lived. It could be a story of friendship and cooperation in the magical community.
Overcoming differences is also a theme. Since they are two distinct characters, they may have different personalities or beliefs. Fanfictions often show how they learn to accept and work with each other's differences, which can be really inspiring for readers.
One more theme is growth. In these fanfictions, we can see Harry, Charlie and Bill grow as individuals. They learn from their experiences, become more powerful in magic, and develop better understanding of themselves and others. This growth is often tied to the challenges they face together and the relationships they build.
One interesting story could be about Harry, Bill and Charlie going on a magical adventure together in a hidden part of the Forbidden Forest. They might discover a new magical creature and have to protect it from dark wizards.
Well, I'm not sure who the absolute best is, but there are some really good ones out there. Some new and upcoming authors might be writing great stuff. You could check out some fanfiction platforms and look for the ones with high ratings and lots of positive reviews.
I'm not sure specifically as there could be many different takes in such a fanfiction. It might involve Harry having a special relationship with Bill and Charlie, perhaps in an adventure or within the wizarding world's social context.
Perhaps in the fanfiction, there is a magical tournament being organized that requires the skills of all three. Harry is known for his courage and spell - casting abilities, Bill for his worldly knowledge and dueling skills, and Charlie for his physical strength and ability to handle dangerous magical beasts. They team up to compete and face various challenges along the way.
Well, perhaps they could go on an adventure together. Maybe they discover a hidden magical place in the Forbidden Forest. They might use their combined skills, Harry's courage, Bill's experience with magical creatures, and Charlie's knowledge of dragons to overcome some sort of danger or mystery.