This is going to be a brief look into the changes I will make to the characters. They won't go in depth, these aren't character profiles. I would consider these notes about the character changes.

Update: I will keep updating this page when it comes to my redesigns. Yes, I am redesigning the cast, at least some of them. The ones I believe need a redesign at least.

Marinette

Interests/Hobbies: Marinette will be more into fashion than the show shows. She will have a number of mannequins of unfinished projects she's got and plans to finish them once the inspiration hits her again. Have her make her own outfits. Also give Marinette more interests. Maybe physics so it could be more natural when she saves the day with Lucky Charm. This is also something random but make one of her idols a main character of Jojo. Maybe Jolyne? She could be a major Jojo fan and maybe link it to her being smart.

Personality: Marinette will be a little ditzy and still a major clutz. But it's something that she is working on and promises to work on it. She is one of those people you don't see mad or upset, only smiling and always happy. But in reality, she's self-loathing and believes she doesn't deserve what she has been given. A loving family, amazing friends and recently, the Ladybug Miraculous. She is a genuinely empathetic person, but that is Marinette's greatest flaw, she's too much of an empathetic person.
When she's Ladybug, she's confident and not afraid to open up to Cat Noir about her struggles. She would also get flustered when he would playfully flirt with her and would playfully flirt back. When Cat Noir would eventually tell her that her feelings weren't mutual, she just smiled and told him it was fine. On the inside though, she was hurt but she was happy that he was honest with her and not lying to make her happy.

Redesign:

Adrien

Interests/Hobbies: Adrien doesn't have many interests or hobbies at the start and over the course of the story, he will eventually have his own interests and hobbies. Most of them will come from Nino as they're best friends but some will also come from Marinette as they will have a lot of friendly interactions and of course he will make his own interests and hobbies later down the line. Maybe Nino gets him into dancing and video games while Marinette gets him into anime and maybe he starts modeling some of the clothes she makes. One of the interests he could pick up is a sport of some kind like track, soccer or even baseball. Any sport for him to be interested in and maybe even join a team.

Personality: Keep it similar to the show but put more emphasis on his loneliness and need to be closer with his dad. His original personality would've been more interesting if we saw the repercussions of his mother's 'death' and his father basically abandoning him. Also some more Adrien and Nathalie bonding because she would've been a good mother figure for him. A few things I would add to his personality is him being more formal at the start because of his upbringing but eventually mellow out later in the story. Something to make it believable that he was raised in solitude is him being awkward about social interactions, mainly with Marinette, and not knowing much slang.
As Cat Noir, keep him the same but not make him a major simp because it's just irritating. Make him like an actual cat, not listening to Ladybug most of the time and acting out on his own. He still trusts Ladybug as a partner, but he has a backbone this time. His flirting also having a limit and being playful with his flirting.

Redesign:

Chloe

Interests/Hobbies: Chloe in the start will be like Adrien and won't have many interests/hobbies and will gain them over the course of the story. The difference between them however, Chloe never thought of her having an interest or a hobby because, well, she was rich. On the inside, she's bored of her normal life. She doesn't have anything going on in her life with her father being the mayor and her mother always away. Her life is mundane as the only person who's with her and cares about her is her butler. Maybe one of the things she would gain an interest in is cooking or even baking.

Personality: Chloe is still the mean and vain person she always is, but she has a talent in manipulation and uses this to get what she wants from people who aren't her butler, who does that without the manipulation. It's shown that the reason why she's the way she is because of her mother, just like the show. Chloe loves her mother and yearns for her love and affection, to which she doesn't reciprocate. Her father doesn't help with him being busy as the only one in her life that cares for her like a parent is her butler, even when she keeps forgetting his name. To give her more of a reason why she acts the way she is is because she feels like if she softens even a little, she would lose her mother in her life. However, she does step up and becomes a better person when she becomes Queen Bee. Though she's still a mean person, you can tell that she means well.
As Queen Bee, she lives up to that name to a T. She acts regal and always cares about how she looks in a fight. A total diva. She would also throw in her little touch of calling everyone in the team her 'worker bees' even when she's not the leader. Even so, she is reliable in a fight and will always have her teammates' backs.

Redesign:

Alya

Interests/Hobbies: Same as the original but make her more of a comic book fanatic. Have her talk about it with Marinette and maybe have marathons with Marinette and Nino from time to time.

Personality: Same as original but with one extra thing. This time, since the love square is flipped, she loves to give Adrien advice on how to win Marinette over. She will also be a shipper and be an avid Adrienette shipper. Alya would also be competitive over ships and will make deals with people, mainly with Nino, over if something will happen with Adrien and Marinette. She will know her limits for her shipping and won't go too far. Later on, she will feel bad for Adrien and try to tell Marinette to ease up on getting with Cat Noir since he's a superhero.

Redesign:

Nino

Interests/Hobbies: Give him more interests/hobbies because he just feels like the boring guy trying to be the chill dude. Make him more of a gamer and maybe also make him interact more with Max. Do more with him being a DJ. If there's a birthday, ask him to make a playlist for the person's party. Maybe Nino is into breakdancing and that's why his transformation is the way it is. It would also be interesting if he was also a geek and an otaku, giving him more reason to be friends with Alya and Marinette at the start.

Personality: Keep him the same as the show. However, his love life needs to change. Keep him being into Marinette for a while until he realizes that his best friend, Adrien, also likes her. Maybe Adrien tries setting them up even though it hurts him deep down. Nino can see this and show remorse that Adrien helped him so much, even though they both liked the same girl. This could bring them closer together. He will also find out Marinette likes someone else, probably have her mention something about either his hair or eye color and Nino will think she's talking about Adrien even though she's talking about Cat Noir. Over the course of the series, he will have moments with Alya where their relationship could build into a romantic one.

Luka

Interests/Hobbies: Keep his interests and hobbies the same, but maybe add a few other things. I could see him being into tarot cards, crystals, charms, feng shui, etc.

Personality: He's still super chill and doesn't usually get mad. Luka is one of those people that when he does get mad, he would be scary. Luka still likes Marinette and tries to get with her and he does. Maybe he could playfully flirt with her, like Cat Noir and Marinette could like him back because he reminds her of Cat Noir. Maybe at one point, Marinette would think Luka is Cat Noir because of his flirty nature. Luka would know that Adrien likes Marinette and they would probably be competitive with each other. After him and Marinette break up, he could probably help Adrien out after learning he's Cat Noir, even though it hurts him.

Kagami

Interests/Hobbies: Same thing with Adrien and Chloe with her not having much interests or hobbies at the start, but she finds an escapism with fencing. Once Kagami opens up and becomes friends with Marinette and the others, she could get into manga since I think it was Glaciator 2 where she gives Marinette advice, she actually gets it from a manga. It would just be funny for her to refer to manga for most things after getting close to Marinette.

Personality: Same as the show, but instead of her going, "If you don't try, I will take Adrien", she could try to make Marinette see that Adrien likes her. Once that proves to be unsuccessful, that's when Kagami will start taking her chances with Adrien and Adrien will probably see some things in Kagami that remind him of Marinette.

Lila

Interests/Hobbies: Not much is known about Lila's interests or hobbies, only having them be mentioned. Maybe she could mention them off-handedly to others. I can see her being into chemistry and have her do some experiments. I could imagine her having a collection of some sort and it could be something that's a little weird but could be cool as well. Maybe items that used to belong to famous celebrities that they gave to her like a signed half drunk water bottle. Though she is a liar so she's most likely lying about her celebrity memorabilia.

Personality: Lila is still the lying and conniving person she is but she's much more of a threat while also not seeming like one. She knows of Adrien's crush on Marinette and sees how close the two are. Even though they're friends, she wants to ruin their friendship for her own selfish reasons. Lila could be trying to manipulate Adrien to give up his feelings for Marinette by making her seem worse than what she is and Adrien could stand up against her. She could be Marinette's friend as well, allowing her to show more of her two-faced nature. Maybe she's a borderline sociopath and there could be a reason for why she's the way she is.

Tikki and Plagg

Personalities: In this rewrite, Tikki and Plagg are gonna be the exact opposites of one another. Tikki is going to be the type of kwami who will hammer down the legacy of the Ladybug Miraculous into Marinette's head and force her to train on specific days. Maybe the two could argue because Tikki's training could get in the way of Marinette's normal life.
Plagg on the other hand, Plagg could care less about Adrien using his powers for trivial things as long as he would get his camembert. He cares for Adrien, but doesn't show it. Tikki would scold him since Adrien has the most dangerous Miraculous and Plagg is being way too lax.

Gabriel

Personality: Gabriel is still a shitty father to Adrien but he still somewhat cares for his son. From what Adrien remembers, before his mother 'died', Gabriel used to get lost in his work but it usually doesn't keep him away from his family. From what Adrien knows, Gabriel took Emilie's 'death' really hard and believes that he just needs his space. His reason to be Hawk Moth is the same as the original but he needs to be less pathetic. Don't have him akumatize the baby many times or have him akumatize the pigeon guy over 72 times. Make him be feared by the people of Paris for real and be able to put some fear in the heroes as well.