As of now, Uta is indeed alive. The story hasn't depicted anything otherwise. Maybe there'll be changes in the future, but for now, Uta's part in the manga continues with them being alive.
Their relationship could start with Uta being initially distrustful of Luffy. After all, Luffy is a pirate and Uta has her own ideas about pirates. But as she sees Luffy's pure heart and his determination to protect his friends and pursue his dreams, she starts to warm up to him. They might then become friends who share their different stories and experiences.
One common theme is power exploration. Fans often write about characters discovering new powers or mastering their existing ones better. For example, in many fanfictions, the main character might find a way to combine different elemental powers.
It's mainly about a story involving magic and family. The protagonist has certain powers related to the wind and there are complex relationships and battles within the story.