Since it's a Naruto fanfiction, Naruto himself is likely to be one of the main characters. But it could also have other important characters like Sasuke, Sakura, Kakashi, etc. depending on how the story is crafted. Maybe there are also some original characters created by the fanfiction author.
In this fanfiction, Naruto is surely a central figure as the title implies his journey of rising from the ashes. But there could be side characters that play significant roles. For instance, a new mentor figure could be introduced who helps Naruto in his rebirth process. Or perhaps an old enemy turned ally. And of course, his friends from the original series like Shikamaru and Ino might also be involved in different ways.
The main character is most probably Naruto as the title is related to his potential story arc. But it's not uncommon for fanfictions to focus on other characters as well. There could be a story about how Sasuke also rises from his own ashes in parallel to Naruto's journey. Or it could be about a group of characters, including Naruto, who together face a situation where they all have to rise up from a difficult or ruined state, like their village being destroyed and they have to rebuild it and themselves.
I'm not sure specifically as there could be many different interpretations in fanfictions. Generally, it might involve a character rising from a difficult situation, perhaps like Naruto coming back stronger after a great defeat, similar to rising from ashes. But it really depends on the author's creativity.
It's hard to say for sure without reading it, but it could include Naruto himself. Maybe he has a different role in this fanfiction, like being involved in the omega - related events in a special way.
There might also be some secondary characters from the Marvel universe that play significant roles. For example, Nick Fury could be involved in guiding the Avengers as they try to rise again. Or characters like Doctor Strange might make an appearance to offer his magical expertise in helping the Avengers rebuild and face whatever threats are out there.
Often, there will be an antagonist or a group of antagonists as well. They could be those who oppose the rebuilding of the empire for their own reasons, such as wanting to keep the power structure as it is in the post - empire chaos or having a grudge against the old empire. These antagonists add conflict and drama to the story.
I don't know specifically as I haven't read this fanfiction. But if it's related to 'Star Wars Rebels' (assuming SWR stands for that), it could have characters like Ezra Bridger, Kanan Jarrus, Hera Syndulla etc. as main characters if the story follows the general themes of the show.
Since it's a fanfiction, it probably still features Harry Potter as one of the main characters. He is the central figure in most Harry Potter - related stories. Hermione Granger might also be a main character, as she is Harry's close friend and often plays an important role in the story's progression. Ron Weasley could be another main character, especially if the fanfiction focuses on their trio friendship.
Often, the main characters from the original Avatar series like Aang, Katara, and Zuko are still central in 'Ashes to Ashes' fanfiction. Their growth and new adventures are explored further.
I'm not entirely sure as it can vary depending on the specific fanfiction. But often, it could be the protagonist who has a strong connection to the past events that are being explored.
I don't know as I haven't read the novel, but I assume there would be Alpha as a main character. There might also be characters who are either friends or foes to Alpha during his or her journey.
Perhaps it has an anti - hero as a main character. Someone who is initially drawn to the rising dark but then has a change of heart. Or it could be a group of characters, like a band of rebels in a dystopian - themed fanfic related to the 'rising of the dark' where they are fighting against an oppressive dark regime.