One potential new member could be a skilled archer from a forest - dwelling tribe. They have amazing accuracy and can use special arrows made from rare materials found only in their forest. Another could be a mermaid or merman with the ability to control water in unique ways, not just for combat but also for things like navigation and finding hidden treasures.
If Luffy kisses Nami, it could cause a stir among the crew. Sanji might be extremely jealous as he has his own feelings for Nami. Zoro, on the other hand, would probably make sarcastic remarks about it. But overall, it could also bring the crew closer as they see Luffy and Nami in a new light and start to think more about relationships within the group.
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.
His anger could slow down the progress of the crew. For example, if they were on a mission to an island and Luffy's anger at Nami stops them from working together efficiently. The crew might get distracted from their main goals as they deal with the internal conflict. In fanfiction, this can be used to explore different aspects of each character's personality and how they handle such difficult situations within the crew.
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.
It could put them in a lot of danger. The World Government would target them. But it could also strengthen their bond as they face the challenges together.
Fem Luffy would probably bring a lot of energy. She might be more empathetic in some ways compared to the original Luffy, which could help in resolving internal crew conflicts. For example, if two crewmates have a disagreement, she could use her charm and understanding to smooth things over.
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 He would likely become more withdrawn at first, but then focus on getting stronger to avenge Luffy if there was someone to blame for his death.
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.