Let me get you started on that Chloe is a sentibeing head cannon because it's one that I share. Idc if it doesn't make sense chronologically, when it comes to the kingdom concept she is always paired up with the other senti children, her parents are the closest people to the agreste family before the start of the show, and her arc is all about free will, whether or not you agree with it's direction.
yes !! from context clues, we know they were all friends for a very long time, I assume at least since college. I can't imagine them not knowing about emilie's fertility issues, the safaris, everything.
I guess if I had to situate chloe's conception somewhere in time, i'd say she could be the second sentikid ? we know that andre and audrey always had a strained relationship, so what if andre borrowed the peacock miraculous to trap audrey because she was about to leave him ? I know this is basically fanfiction territory at this point but let's just imagine this scenario for a moment.
so chloe spends her life without a mom and on top of that, her father isn't really present either. he spoils her but doesn't give her the structure or emotional support needed for a child to grow up properly. maybe he even isolates her voluntarily because he likes having someone who depends on him ? she's his only remaining family, so he traps her in this golden cage where she basically gets what she wants. like that, chloe grows up knowing what buttons to push for her father to give her what she wants.
simultaneously, chloe still wants her mother's approval. all chloe knows is materialism, so she takes care of her appearance more than anything. it's also what society praises the most, which only reinforces her obsession with her image. she needs to look perfect to maybe one day become the perfect daughter for her mom.
and that's how you get a mean girl. she lacks personal identity, and her demeanor is a direct result of her lack of self-worth. chloe is powerless in her life. the only way for her to take control is to act a certain way. she's also emotionally unregulated, which means anything can lead her to have a meltdown/tantrum. she only knows how to sabotage people, not how to love. when she sees her mother again, she tries to behave just like her, to show her they're on the same level. but it's not enough, chloe is told she's not perfect enough. so now she wants the same power her parents have, because then they'll finally see her as capable.
so if actually chloe hates marinette because she has the parents chloe dreams of did we think about that ? while ladybug is kind of a maternal figure that chloe looks up to
maybe I made all that up because I actually don't like andre and I'm not over the fact that he gets a redemption while his wife and kid are just written off as evil lol...anyway all of this is real because I said so