Interceptor Javelin (Official thread)

Answers:

It's all in the legs.
Interceptor Javelins have stilts built in - essentially lengthening the body.

That has the net effect of making this unisex suit appear thinner because the legs are longer.
However, a male pilot will still fit because the suit is much taller than a normal human.

For a unisex suit to work, it does require a little additional shaping in the hips and chest so that both pilots fit, but nothing a little padding can't sort out for immersive comfort, I'm sure.

Pilots may upgrade the personalization of their Javelins with different armor pieces if they prefer a more masculine or feminine silhouette, though it's the same unisex suit underneath.

Don't forget, it's the most agile, fast and precise of the Javelins, so the suit's inevitably going to be a bit clingy.

A rudimentary graphic to explain the concept (apologies for my poor image composition skills, but you get the idea):



And it's been done, life size.