There may be a fanfiction where Anakin's redemption arc is extended to include getting his body back. It could be that his good deeds in the afterlife, like guiding Rey or helping other Jedi spirits, earn him the chance to be fully restored. This type of fanfiction would explore the themes of redemption and second chances in a really interesting way.
One interesting fanfiction could be where Anakin gets his body back through some ancient Sith or Jedi ritual. Maybe a hidden Jedi Master discovers a way to reverse the damage caused by his transformation into Darth Vader.
With Jiang Cheng, his relationship might be a bit more complicated. There is still a lot of unresolved history between them. Wei Wuxian might try to mend their relationship, but Jiang Cheng's pride and past grudges could make it difficult. However, the fact that Wei Wuxian has his original body back could be a starting point for them to have more honest conversations.
One possibility is that Wei Wuxian would seek revenge on those who wronged him in his previous life. He might start by confronting the Jin Clan who were involved in many of the dark deeds. With his original body, he would have all his old powers back at their peak. He could also try to reconnect with Lan Wangji in a more physical and less restricted way compared to when he was in Mo Xuanyu's body.
There is no such appropriate fanfiction. In the Star Wars universe, which Anakin belongs to, there are certain values and moral codes. This kind of plot would completely shatter the integrity of the story and the characters, and it's not something that the fan community or the general public would tolerate.
It could be a new and powerful dark side user. This character might have emerged from the shadows, having trained in secret, and their sole purpose is to take down Anakin as he is seen as a threat to their plans for galactic domination.
It's a very bad and unethical idea. It might be the product of a person's deviant mind, but this has no place in the world of fanfiction. Fanfiction should be about building on the positive aspects of the original work, exploring character growth, relationships in a proper way, not creating such immoral and repulsive scenarios. In the case of Anakin, his story is about his fall to the dark side and redemption, not something as immoral as this.
It could be the Separatists. They might see Anakin as a valuable hostage to use against the Jedi and the Republic. His skills as a Jedi Knight make him a prime target for them to gain some sort of leverage in the war.
Yoda would be another character. As one of the wisest Jedi, he could sense the strange situation with Anakin and offer his unique perspective. He might be more patient with a child - like Anakin, teaching him important Jedi lessons and trying to ensure that Anakin doesn't go down the same dark path as he did in the original timeline.
Well, if we look at the 'Naruto gets his parents back fanfiction', Naruto's character development might take a different turn. Instead of relying solely on his friends and mentors like Iruka and Kakashi, he'd have his parents' direct guidance. His father, Minato, could train him in advanced ninjutsu. His mother, Kushina, could give him all the motherly love and care he was deprived of. This would likely make Naruto more confident and perhaps a bit more relaxed as he wouldn't have that deep - seated longing for family anymore.