So, with the latest Raiders trailer, time for a new headcanon (or two).
With Frye giving the Mechanic their new haircut/style (and presumably any others after that during character creation?), headcanon that she also cuts her sister's hair. They're very upset that she's gone missing because, aside from the expected missing family member drama, their hairdresser is gone! They have another, but she doesn't do it right! Frye you have to come home now!! :( :(
Also headcanon that she got good at it in middle school by cutting her own/styling Shiver's hair. Shiv wanted a certain hairstyle but didn't want to ask her family/ask at the stylist's while her family was There, and Frye was like "oh, I'll do it!". It might not've been great the first few times, but Shiver liked it anyway. Frye still does it for her (and is much better about it now).
When Shiver got home that first time after Frye did her hair, her family was probably like "Your hair looks different." ("Yeah, Frye did it for me.") "I see..." [long awkward silence and it's never mentioned again but there's a sort of judgy feeling in the air...]