I'm not sure specifically as there could be many different 'Moshuko Tensei' light novels. It might be about a character's reincarnation and their new life journey, often with elements like magic, adventure, and character growth.
Online platforms are a great option. Websites like Amazon often have a vast selection of light novels, including 'moshuko tensei' if it's popular enough. You could also check specialized Japanese bookstores' online shops, as light novels are very popular in Japan.
In certain fanfic concepts, Naruto could learn Edo Tensei from Kabuto. Kabuto, having mastered the jutsu, might decide to teach Naruto for some reason. It could be because he sees Naruto's potential to use it in a more positive way compared to how he misused it. Naruto, with his strong sense of justice, would then try to modify the jutsu to be less evil - like not using it to bring back people against their will.
Hard to say. It could be on hiatus, but without concrete information, it's difficult to give a definite answer. Try following the mangaka's social media or the manga's official website for the latest.