One possible plotline could be them dealing with the challenges of Kakashi's ninja duties while maintaining a marriage. Another could be Rin adjusting to life in Kakashi's village.
There could be a plotline where they discover secrets about each other's pasts that they hadn't known before getting married. This could cause some tension at first but ultimately bring them closer as they work through it. Or perhaps they take on a mission together as a married couple, which tests their relationship and their skills as ninjas.
A plotline might involve them having a child and the difficulties and joys that come with raising a ninja - in - training. Also, they could face old enemies who target them because of their relationship.
Yes, there are quite a few. You can check out some popular fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'kakashi and rin married' in their search bars, and you'll likely find some interesting stories.
One possible plotline could be a what - if scenario. For example, what if Obito didn't 'die' and he and Rin finally confessed their feelings and shared a kiss. Another could be a time - travel plot where Obito gets a chance to go back and change things, leading to a kiss with Rin.
A possible plotline could be that a new enemy targets Kakashi because of his distinct face features, believing there is some hidden power in his appearance. Naruto then has to protect Kakashi. Another plotline could be a magical spell that gets cast on Kakashi's face, changing his expressions uncontrollably, and Naruto tries to find a way to break the spell.
One possible plotline could be that fem Naruto, being a big admirer of Uchiha Rin, tries to follow in her footsteps. Maybe she wants to learn the same jutsu or have a similar impact on the village as Rin did.
One possible plotline could be that Naruto somehow ends up in the Fate/stay night universe and meets Tohsaka Rin. They could team up to face a common enemy that threatens both their worlds. Another plotline might involve a magical accident that fuses their powers and they have to learn to control it together.
One possible plotline could be that Kakashi realizes his feelings for Sakura during a difficult mission. Maybe they are in a life - or - death situation and he suddenly realizes how much she means to him.
A plotline could revolve around Sakura getting special training from Kakashi. He could pass on his unique skills and knowledge, like his lightning - style jutsu or his stealth techniques. This would make Sakura an even more formidable ninja and also strengthen their father - daughter bond.
One plotline could be that they face difficulties during the pregnancy due to their ninja duties. Maybe they have to hide their pregnancy from enemies or deal with the physical strain of being a ninja while pregnant.
One possible plotline could be them dealing with the unexpected pregnancy in the middle of their ninja duties. They might have to balance their responsibilities to the village with preparing for a new life. Another could be the reactions of their friends and comrades in the village. For example, how Naruto or Tsunade would react to the news.
One possible plotline could be that Kakashi is in a life - threatening situation during a battle against a powerful enemy. Naruto, seeing no other way to save him, uses a powerful and self - sacrificing jutsu that costs him his life. Another plotline might involve Naruto making a deal with some dark force to save Kakashi, but the price is his own life. Or perhaps in a mission gone wrong, Naruto takes a fatal blow meant for Kakashi.