Maybe there's a villain, a power - hungry man who wants to use the girl's powers for his own evil plans. And of course, her family members, like her parents who might be worried about her new - found abilities but also proud of her in the end. There could also be other kids in her school or neighborhood who are either friends or foes depending on the situation.
In addition to the main girl, there could be a group of rebels. They are fighting against an oppressive regime in their world. The girl of tomorrow might join them and together they work towards a common goal. There could also be a love interest, a boy who she meets during her adventures and they develop a relationship while facing all the difficulties together.
There could be her best friend who is always by her side and gives her moral support. Also, a mentor figure, like an old wise woman who teaches her how to control her powers.
I'm not sure as I haven't read the specific novel. But typically in novels, the main characters could be ordinary people trying to navigate their lives in the context of the themes related to the title, like dealing with the passage of time.
Obviously, the 'ugly girl' herself would be a main character. She is the center of the story and the one whose diary we are presumably reading.
One possible plotline could be about a character who is constantly waiting for the next day to start a new life or make a change. Each 'tomorrow' passes by, and they keep putting things off. Another could be that the world in the story is in a cycle where every 'tomorrow' is a reset of some sort, and the characters are trying to break free from this cycle.
Well, it could be about a girl who has special powers and she uses them to save her town from an evil force. Maybe she discovers her powers gradually throughout the story.
Naruto is surely going to be one of the main characters. After all, it's a Naruto fanfic. Sasuke is also very likely to be there as his rival and friend. Sakura might also play an important role.
A young Asian student could be a main character. They are constantly under pressure to succeed in school and get into a good university. When they gain the anterograde ability, they use it to ace their exams and impress their teachers and parents, but soon realize that there are consequences to relying too much on this power.
I'm sorry, I don't know the author of this 'tomorrow and tomorrow and tomorrow a novel' as the title is not very common in my knowledge. You could try searching for it in a library database or a good book search engine.
It seems that the 'tomorrow girl' would be the main character. But it's also possible that in the 'other stories' there are other important characters who share the spotlight. Maybe there are different main characters in each of the individual stories within the collection.
I don't know as I haven't read the novel, but they could be soldiers, leaders, or civilians caught up in the events of the future war.
I don't know the specific main characters in this novel as I haven't read it.