Lute is new for me and I haven't written her yet as being interested in anything other than pining/grieving over Adam depending on canon point.

So straight! That said, I wouldn't say there's no circumstances in which I could see her with another woman so if she had real chemistry with someone I'd try it and see how it worked

Definitely straight until proven otherwise though.

Ari is bisexual, although she wouldn't use the term. Most people in her setting are bisexual, it's sort of the default assumption.

She finds heteronornativity weird because of it.

But also! Her people's categories are different. They have words for being attracted to men, women, both or neither. So straight men and lesbians go in the same 'attracted to women only' category.

Gender roles in relationships are not really a thing for them, they think this categorisation makes sense.