stream of consciousness here we go -- there really is no rhyme or reason to this, it's just random thoughts that have collected
largely a loner even within the yellowjackets but probably gravitates toward nat the most. the "burnout" culture is not that dissimilar to the "sukeban" culture that she had been steeped in until her family moved to wiskayok
also understands a lot of tai's neuroses of being a person of color, though they have sort of opposite journeys of yumi shedding the respectability while tai tries to chase it as much as she can -- irony for the adult timeline where yumi starts out similar to tai as a high-achieving, successful woman of color
would have joined tai's expedition south in the teen timeline because it's her nature to do something rather than sit around and wait
socially within the team, she floats between groups but doesn't have a fully settled place or person. she's cordial with everyone but she's very socially aware of the dynamics that are underlying every action because it reminds her of her time in tokyo. for that reason, she doesn't rock the boat, particularly with shauna, but she acts as a steady, silent presence if needed
in the adult timeline, she's in private security and i think it's not unreasonable that she was aware of both lottie and melissa and their locations. her paranoia and OCD would have her keeping tabs on everyone (not unlike misty) and using her resources to do so. she wouldn't do anything with that information unless it threatened her, but she would have it
largely absent from s1 shenanigans, despite having received a blackmail postcard from jiff, and doesn't show up until the reunion
sticks around after hearing about travis' death / the blackmail and teams up with misty when nat goes missing. tbh walter can be there too, yumi will just hate it twice as much
everything in lottie's compound goes down as it does in canon, except yumi is also there. afterwards, she goes back to the west coast to try and ward off bad press stemming from the incident and protect her company
s3 timeline, she's fighting with her board to keep control of her company. they use the s2 antics and the fact that yumi just disappeared for weeks as reasoning that she's unfit to be the head of the board
rather than fighting a lost cause, yumi finally gives in to the idea that this is what the wilderness has always wanted, for the yjs to finally recognize that they need to be together and feed the kami that they brought back with them (i never said she wasn't as crazy as the rest of them)
as mentioned above, i'd be interested in playing it in a way where yumi was aware that melissa was still alive and simply held that information close to her chest. as more of an outsider within the group, which is a feeling that compounded over the years that yumi kept herself isolated from the others, she would have had no reason to reveal that secret to the others -- mostly meant as a way of depicting yumi as standing on the fringes of this group with no fierce loyalty to a single group or person
when she hears shauna and the others are going to go find melissa, she tries to get there ahead of them to warn her. shauna arrives shortly after she does and assumes that melissa and yumi are in cahoots together while melissa assumes yumi led shauna to her
yumi tries to convince both of them that the wilderness wants them to work together, not against each other. melissa is rightfully like "you guys are nuts" and books it, but gets brought back by tai, van, and misty
yumi leaves with misty, realizing that this is not going to end well and if she wants her company back ever, she can't be at the scene of more shenanigans
after everything, tai calls yumi and misty to talk about shauna. when leaving the diner, yumi calls melissa unbeknownst to the others and tells her that they need to talk