I'm afraid I can't name the main characters. Fanfics can have a wide variety of character types. In this 'a lifetime of chances fanfic', the main characters might be characters who are in desperate need of these chances. They could be characters trying to escape a difficult past, or they could be characters seeking to achieve a great goal and these chances are what they rely on to get there.
Since I haven't read this fanfic, I don't know the main characters. It could be original characters created by the fanfic author, or it could be based on characters from an existing work that the fanfic is related to.
It usually has unexpected plot twists and well-developed characters. The storylines are often emotional and engaging.
Fanfics are all over the place in terms of themes. 'A lifetime of chances fanfic' could potentially be about a character's journey through different scenarios where they are presented with one chance after another to change their fate. It might explore how they grow, learn, or make mistakes with each new opportunity.
It's hard to say for sure without reading it, but it could be Harry Potter himself. Since it's a Harry Potter fanfic, he's likely to be involved. He might be the one getting a second chance at something important, like saving Sirius Black.
The main characters could also be entirely new characters introduced in the fanfic. The author might create someone who has a unique connection to the events of the original series and is given the task of changing things. However, it's also possible that classic villains like Cersei could be main characters if the fanfic is about giving her a second chance at ruling, perhaps with a different approach this time.
Obviously, Harry Potter would still be one of the main characters. Since it's about second chances, he might be dealing with things he didn't get to do right the first time. Hermione Granger would also be a key character as she's always been resourceful and could play a big role in making the most of these second chances. Ron Weasley too, as he's Harry's best friend. And perhaps some characters who were on the fringes in the original, like Luna Lovegood, could step into more prominent roles this time around.
I'm not sure specifically as there are many novels with this title. But usually, there would be a protagonist who is the one most actively taking chances.
I don't know for sure as I haven't read it. But it could be Ruby, Weiss, Blake, and Yang as they are the main characters in the RWBY series and often feature prominently in fanfics.
Since it's an Eriza PLL fanfic, Eriza is most likely one of the main characters. There may also be other characters from 'Pretty Little Liars' that interact with Eriza in the context of this love story. But without reading it, it's hard to say exactly who else.
Batman is obviously one of the main characters. He's the one who offers second chances. And there are likely to be some of his classic villains like the Joker or Two - Face, who might be on the receiving end of these second chances.
Since it's a Naruto - based fanfiction, Naruto is very likely to be a main character. Other possible main characters could be his closest friends and allies. For example, Shikamaru, who is known for his intelligence and often plays an important role in the series. It's also possible that some of the antagonists from the original story could have a different role in this fanfiction and be considered main characters, like Orochimaru if the story focuses on redemption or a change of his character. But again, without reading it, this is just speculation.