Nintendo confirmed shiver is a woman.I figured it was similar because Ninitendo didn't refer to Shiver as a him or her, which is how Bridget is referred to in some of the promotional material, so I'm assuming Shiver is supposed to be another otoko no ko type character.
It's probably off topic, but the funnier thing is that it'll piss that crowd off no matter what happens. If they use pronouns, "you're destroying non-binary representation!". If Shiver is a otoko no ko, then it can be seen as a straight "relationship" because these people don't know what yaoi/yuri baiting is, so they can only see friendships as an actual relationship (which is how they view Pearl and Marina from 2).
Cringe article but has the fact they reached out and got an answer.