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.
Sure, an English version exists. However, it could take some effort to find a reliable source for it. Also, keep in mind that different editions might have different features or extras.
The characters in the light novel could be extremely well - developed. Each character might have their own goals, dreams, and flaws. Their growth throughout the story can be very interesting to follow. For instance, a character who starts off as shy and timid might gradually become more confident and assertive as the story progresses, which is a very satisfying arc for readers to witness.
I'm not entirely sure which 'shin no nakama light novel' you specifically mean. There are countless light novels out there. If it's a relatively new one, it might be a bit harder to find reviews or detailed information right away. You could try searching for it on some light novel fan forums. There, fans often discuss new and interesting light novels, and they might be able to give you more insights about this 'shin no nakama light novel'.
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.