Well, the main character is surely the hell's princess. Besides her, there might be some sort of mentor figure who has taught her the ways of the hellish world she lives in. And perhaps there are other princes or princesses from different parts of hell who are either her friends or foes in the story of the novel.
I'm not sure about the specific main characters in this 'hell's angels novel'. But it's likely that there would be some central figures within the Hell's Angels. It could be an older, more experienced member who has a lot of stories and wisdom to share. And then there could be a younger member who is eager to make a name for himself. Additionally, there might be female characters who play important roles, either as partners of the members or as strong individuals within the group's periphery, adding different perspectives to the story.
Since I'm not familiar with 'hell's heart novel', it could have a diverse set of main characters. There might be a brave hero or heroine who is on a quest related to the 'hell's heart'. There could also be some sidekick characters who support the main character, and perhaps a powerful villain who wants to use the 'hell's heart' for their own evil purposes.
Obviously, the Princess of Hell would be one of the main characters. She would bring her own set of characteristics, motives, and powers to the story. Harry Potter himself would also be a main character as the story is set in his world. He would be the one to either oppose or befriend the princess. Hermione and Ron would likely be involved as well, providing support to Harry and having their own reactions to the new and strange character from hell.
Gabimaru is one of the main characters. He is a very tough and skilled fighter.
It's also possible that there is a villainous character in the novel. In a place like Hell's Half Acre, there could be someone or something that is causing trouble for the other characters, making their lives even more difficult.
There could also be a mentor - like character. Someone who has either been through a similar experience before or has some special knowledge that can help the protagonist in their journey through hell and back. For example, an old wise man or woman who gives crucial advice at key moments.
Since I haven't delved into the 'hoarding in hell novel', it's hard to say for sure. However, it's likely that there is a central character who has the hoarding trait. There may be some sort of guide or mentor figure, perhaps an otherworldly being who tries to influence the hoarder's actions. And of course, there could be enemies in the form of hellish creatures that oppose the hoarder's activities or try to take advantage of their hoarded items.
I don't know for sure as I haven't read it. It could be a group of outcasts or people with troubled pasts.
I'm not sure specifically as there could be many novels with this title. However, generally, there might be a protagonist who is at the center of the 'descent into hell' experience. This could be a flawed character, perhaps someone who has made a mistake or is being forced into a difficult situation.
It's possible that the main character is a fallen angel or a damned soul. There could also be otherworldly beings like demons or spirits that play important roles in the story. Without reading the graphic novel, it's all speculation, but these types of characters are common in stories about hell.