Yes. The conflicts between Sanji and Luffy in the manga often stem from complex circumstances and character developments that drive the narrative forward.
As of now, Sanji is very much alive in the One Piece manga. The story keeps unfolding with him as a vital part of the plot. The author hasn't written his death yet.
For Nami, her intelligence and cunning are key. She could use her smarts to get Sanji out of trouble in the fanfiction. Also, her love for money and treasure can add an interesting dynamic. For example, she might convince Sanji to go on a dangerous adventure in search of a valuable item, promising him new ingredients for his kitchen.
It can be developed through shared hobbies in the modern world. For instance, if they both like extreme sports, they could bond over skydiving or surfing. This would not only bring them closer but also show a different side of their characters.
Their relationship in the Zoro x Sanji Christmas fanfic could be presented through a series of challenges and reconciliations. For instance, when they are tasked with getting a Christmas tree for the ship. Zoro wants to just chop down the first tree he sees, but Sanji has very specific requirements. They argue, but then realize that by combining their ideas, they can get the perfect tree. This pattern of arguing and then coming together could be repeated throughout the Christmas celebration, showing the complexity and depth of their relationship.