I haven't read all of her supports, but my general understanding is that they're a mess regardless of her orientation. I don't really think I'd be comfortable pairing someone with anyone if they had to try so hard to convince them they like them. If someone likes someone else they'd know, and that's a level of uncomfortable on its own.
I still think there was at least one support that stated she didn't find boys unacceptable as romantic partners, which I think might be what's behind the biromantic label, unless that wasn't translated properly. I'm trying to avoid reading any more because I'm trying really hard to avoid spoilers (although the way some people title their YouTube videos already confirmed some things for me).
My main thing is..
WHY CAN'T I MARRY CAMILLA (as a girl). 8(
The boob belt will forever bother me but her VA is really doing it for me. Plus her face is actually incredibly adorable.
And I feel like from what I've seen, she makes a lot of jokes that imply she's not completely straight..
She says to Foleo that boys are okay, but she prefers girls so much more. Doesn't seem like thats true with her other supports tbh. It's very vague.
Also yeah she flirts with Hinoka a little bit.
Yeah I dunno. It's possible that the game was coded that only males and females can have supports and it was too late to change it so they wrote in what they could? I'm not really sure.
I don't think there should be too much hassle, since you can still get a kid if you marry Zero or Tharja Clone. Instead of giving birth you like adopt them or something? I think that was their reasoning. Not too sure though.