Anakin's mother, Shmi, would likely be a very important character. Since Anakin is not being trained as a Jedi, he would be more focused on his family. Shmi's influence on Anakin would be even greater, and she could play a role in guiding his actions and decisions, especially in relation to the local community on Tatooine.
His mother, Shmi, would definitely be a main character. She could play an even more important role in Anakin's life, guiding him in using his abilities for the good of Tatooine. Also, Watto, the junk dealer, could be a significant character. Their relationship might evolve from one of slave - owner and slave to something more complex, like a grudging friendship or a business partnership as Anakin grows older and more skilled.
The main characters would be Anakin Skywalker and Darth Plagueis. Anakin, a powerful Force - sensitive, is the focus of the training. Darth Plagueis, a Sith Lord, brings his knowledge of the dark side of the Force to the table. There may also be other supporting characters like the Jedi who might notice Anakin's change in behavior or Padmé, Anakin's love interest, who could be affected by his new training and the path he is on.
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.
The main characters would surely be Anakin Skywalker and Count Dooku. Anakin is the protagonist in a sense as we would see his development through Dooku's training. Dooku, on the other hand, is the one who imparts his knowledge and skills, and his character would also be explored in terms of his motives for training Anakin.
Obviously, Anakin Skywalker and Revan. Anakin is the one being trained, so he will be a central figure. His growth and development under Revan's tutelage will be a major focus.
Obviously, the members of the Jedi council would be main characters. Yoda, for instance, would play a crucial role. His wisdom and experience would lead him to question Anakin's motives and the truthfulness of what he says.
I'm not sure specifically as there could be many different takes in such a fanfic. But generally, it might involve Plagueis using his dark side knowledge and skills to train Anakin, perhaps leading Anakin down a different path in the Force compared to his canon training. Maybe Anakin would learn unique Force abilities or have a different view of the Sith and Jedi conflict.
Another plot could be that Anakin, without Jedi training, still has a connection to the Force but doesn't understand it. He might have strange dreams and premonitions that he tries to make sense of on his own. This could lead to him seeking out different kinds of mentors, not Jedi, but perhaps old hermits or wise women in the deserts of Tatooine who have a different perspective on the Force.
There could also be a sidekick or a fellow Jedi. Maybe a young Padawan who looks up to Anakin and is constantly by his side. This character could provide some comic relief or be a catalyst for Anakin's growth in different situations.
In this fanfiction, the plot could center around Anakin's struggle with the two different ideologies of the Jedi and Dooku. Dooku, as his trainer, might expose Anakin to the Sith ways. This could lead to Anakin having internal conflicts, as he has to decide whether to stay loyal to the Jedi or follow Dooku's path. His training could involve learning more aggressive and unorthodox Force abilities that are frowned upon by the Jedi, and his interactions with Dooku could gradually change his view of the galaxy and his place in it.