in 'The Twins' Jonny mentions that Snow has long hair and Rose has short hair. I really enjoy the amount of physical difference in this, as well as the practicality/symbolism of it. Snow is a diplomat fighting for peace, long hair represents freedom (what she is working toward) requires a lot of self-care, time, etc. to maintain things that a well-loved diplomat would likely have a lot of. compare this to Rose who is a solider, they likely would not have the resources to be able to maintain this hair as well as the inefficiency of long hair combat (this is coming from experience, my hair BARLEY goes past my shoulders and I still need to tie it up while doing martial arts).
HOWEVER, then their positions are somewhat swapped. Rose is now the one in King Cole's court (though she's, y'know, kidnapped and unconscious. the point still stands.) and Snow is now the one on the battlefield, as General White. so, wouldn't it be cool if while in her glass case, Rose's hair grew out, and for whatever reason Snow's has been shortened? (Personally, I think this would happen during the attack, during Snow's Flight Jonny say she "lost much of herself in the process" and I've always interpreted this as her like, loosing limbs and shit, leading to her needing prosthetics as a general, and also could be a good point for her to have the hair like, torn off in some way. she simply kept it short cuz it was more efficient. also feel like having both her and Rose's change in hair being nonconsensual helps to emphasize that this role swap was something they were thrust into rather than fully chosen by them.)