in yellowjackets s3, lottie says to callie: “shauna is jealous because you're just like her but more”.
callie obviously understands lottie's words as a “you're just like your mother” and this is what shocked and scared her enough to push lottie away which ultimately kills her.
but what if lottie didn't meant what we and callie understood?
what if “you're just like her” refers to callie being a lot like jackie?
because why would shauna would be jealous of callie being like herself when even if shauna is a narcissist she's very aware of the kind of monster she is?
shauna kills, hunt and eats people out of pleasure, jackie and callie don't kill anyone because they want to. in fact, when callie does kill someone for the first time is purely out of fear and some kind of self defense. lottie was grabbing her, invading her personal space and telling callie the things she feared the most: “you're just like your mother but worse” but even then, they don't get off on the violence of murdering someone like shauna does.
callie and jackie were innocent teenagers, even in the bad things they do, they're still teens doing the kind of things you do at that age. both of them loved shauna (in different ways obviously) and wanted to be close to her no matter what.
both ultimately knew what shauna was and they loved her anyway.
in her last moments, jackie dreams of her friends and wants to go inside the cabin because the thing she craves the most is to be with shauna again. to be forgiven, even if she didn't do anything wrong.
if she has to be the bad one and apologize to be with shauna once more, she's willing to.
and that makes a parallel to callie, a doomed daughter of a mother incapable of loving her because she's still traumatized by losing a son and her friend in the wilderness. even if shauna can't find love inside of her to give callie, callie loves her mother unconditionally.
she knows her mother is crazy, she grieves and suffers because she wants to understand what shauna went through and still, she has a heart big enough to still love her even if shauna put her in danger a thousand times.
callie and jackie both have enormous hearts, and they are capable of loving shauna through all her craziness and violence. they know what shauna is, and they cherish her anyways.
the only thing they ask in return is to be loved back by her.
and why is shauna jealous?
because callie being like this only means that somehow she's more close to jackie than shauna herself ever was even after she fucking ate jackie. shauna is not capable of loving anyone fully but herself, that is exactly what killed jackie and hurted callie all her life.
this incapacity to love as they do, is what she envies of callie. because she is indeed like her, but more.
shauna may carry jackie within herself, but she never felt her warm like jeff and travis did (this being the reason why shauna starts the affair with jeff and why travis is capable of ragebait her by telling her “my favorite thoughts are jackie's”), she never fully understood jackie like callie unconsciously does by being so much like her and she has to carry with the weight of being the one responsible for jackie's death.
so yeah, she's jealous as hell.
that's why she has a crash out when she sees callie with the necklace, it's too much for her handle.
callie dressed up (without knowing) like jackie for a party. she wore her necklace because lottie gave it to her. she's just so much like her, shauna gets terribly confused and upset and this is not new: she's been confusing them since callie was born.
don't forget, callie can be another nickname for jacqueline.