Shanks might interact with Luffy's crew in a very friendly and father - like way. He could pat the crew members on the back, give them words of encouragement, and share his experiences with them.
In fanfiction, when Shanks meets Luffy's crew, it could be a very emotional reunion. Shanks might be impressed by how much Luffy and his crew have grown. He could see the strong bonds within the crew and be proud of Luffy for leading them so well.
They would probably be very surprised at first. After all, they might not have expected to ever meet Luffy's mother. Then they would be excited to learn more about Luffy's past from her.
Most of the crew would be excited to meet the people who brought Luffy into the world. They would see it as an opportunity to understand Luffy better. Chopper might be a bit shy at first but would soon warm up and start asking a million questions about Luffy's early life, like what kind of diseases he had as a kid or how he grew up so strong.
Nami would probably be devastated. She has been with Luffy through so much, and his death would be a huge blow. She might become more withdrawn and serious, as Luffy was often the one to bring out her lighter side.
Obviously, they will support Luffy all the way. He is their captain, and they have complete faith in him. They have been through so much together, and they know Luffy's strength and determination.
If a marine joins Luffy's crew in a fanfic, it could be quite interesting. At first, there might be a lot of distrust among the crew members. After all, they've been fighting against marines for a long time. But if the marine has a strong sense of justice that aligns with Luffy's own view of right and wrong, they could gradually be accepted. For example, the marine might bring in some new combat techniques or knowledge about the navy's operations that could be useful to the Straw Hats.
Zoro would be deeply affected. He has sworn to follow Luffy and his death would be a huge blow. He might feel like he failed in his duty to protect the captain. He would likely become more withdrawn at first, but then focus on getting stronger to avenge Luffy if there was someone to blame for his death.
For the Straw Hat crew, it would be a major shift. Sanji would be beside himself with excitement, always eager to please and protect. Zoro would have a complex reaction. He might be a bit more gentle in his challenges to her but also be on high alert to make sure no one takes advantage of her. Nami would be thrilled to have a female companion on board. She could teach Luffy about things like haggling in a more feminine way. Usopp would be the one to spread the news around the ship in his own humorous way. Chopper would study if there are any health differences for a female Luffy. Franky would be focused on making the ship more comfortable for her, like adding softer seating areas. Brook would be using his skeletal charm to make her laugh and keep the crew's spirits high.
The Straw Hat crew would probably be very surprised at first. Nami might worry about how Hancock's presence would affect their finances, since Hancock is used to a more luxurious lifestyle. Usopp would be in awe of Hancock's beauty and powers. Chopper would be excited to have Hancock around, as she could potentially teach him about different kinds of medicine from Amazon Lily. Zoro might be a bit skeptical at first but would come to accept it as long as Luffy was happy.