Zendaya and Hunter Schafer are clearly, consistently underweight — a solid point or two over the border. I actually find the Zendaya comparison quite favorable to Hunter: both being tall and skinny, they look at ease with each other in the frame. It would have been harder for Hunter to pass next to a Mila Kunis type. As it is, Hunter has narrower hips and a broader ribcage than Zendaya, but the difference isn't so terrible that a viewer without our special strain of trans Internet poisoning would clock it. There are female women with inverted triangle bodies, too (see Hannah Waddingham, Vittoria Ceretti, Kaia Gerber, Charlene of Monaco). Hunter doesn't seem out of place in that pack unless you see her nude, which most people don't.
For all normal purposes — casual, clothed, without trans shit on the mind — I'm sure Hunter passes. It helps that her voice is pleasant, which is maybe more important than body, and that she embraces androgynous coolness rather than grasping for a hyperfemininity she doesn't have. The gangly art kid look suits her and doesn't set off inauthenticity sirens like many trans people do when they try too hard. I'm convinced that for everyday passing, the minimal formula for maximal success is 1) voice + 2) enough thinness to prevent the torso from looming large over the hips + 3) styling that looks like the choice of a human woman rather than a male gaze parody. Strength training for thighs and ass is a plus, of course, but not essential because clothes can add visual volume.
At the end of the day, if a trans woman wants to pass, I think she should put her energy into the broad strokes and not get too mired in the details. The details will never be right because fighting biology is fucking hard. Making a male resemble a female — truly a female, and not a caricature of femininity — is one of the toughest magic tricks in the social world, and like magic cannot be expected to maintain the illusion without props, beyond the intended context. If you have to take a stab at it for whatever reason, the goal should be everyday functionality. Nail the big things (already a herculean task) and move on. Body obsession is bad for the spirit. You can feed it scraps without being consumed, but you have to put your foot down somewhere.
The problem with most MTF passing attempts is that they misidentify the big things as HAIR and CLOTHES and MAKEUP and BOOBS and then move to shit like skin texture, removal of all hair below the eyelashes, "feminine" gestures that no natural woman would put on, and lazy attempts at voice that raise the pitch but fall far short of sounding female. Claire's voice sounds forced even after seven years of transition. That's a weird choice for a voice teacher, so I have to assume the badness is unintentional. I can't wrap my head around it: going all the way to SRS without nailing the voice. It's like lifting weights on a low protein diet. Doing the most on a foundation of sand.