The thing for me is that I like when a character has a wealth of non romantic relationships.
Siobhan has a different relationship with Ana to the one she has with Damien, but they’re both friendships.
She has a different relationship to Liza than she does Lacer, but they’re both mentors in a way to her.
Her relationship with Oliver is different to all four. Yes, sometimes he teaches her stuff, but he also relies on her. He knows her in a way that no one else does. They do have a mutual attraction and they find each other fascinating. It’s also one of the safest love affairs she could have because he does know her, he also knows that she’ll walk away from him and has her own resources. She respects him more than she does her school friends because he’s doing something ambitious, something meaningful and he’s done it with his own two hands. It’s a little like Damien’s feelings for Sebastien - but turned way down and much tempered by sense and cynicism.
With anyone else, she has to either come clean or there’s the threat of discovery down the line. It makes a relationship very shaky. Damien has evidence of her working blood magic on him, if he ever thinks about it. He has that nagging feeling about the fake ring which he might shake loose in future. He’s also the darling younger brother of the head of police.
Ana has Gervin resources and has spent a lot of time observing Sebastien, her little sister has even ferreted out the details of the Undreaming Order’s day to day functioning.
Lacer…Lacer has far too much power over her. He could have her expelled, he could track her down and rip all the details from her mind that he didn’t last time. Liza similarly has a great advantage of strength and experience over her. Liza is the one I’d root for most after Oliver, but it wouldn’t feel good. It’s nice to have an older female friend to just chill with sometimes and rely on.
I think it’s good and enjoyable having secondary characters who aren’t there for romantic roles but to have genuinely valuable and enriching relationships with the main characters. Friends, family, mentors - it’s just that, regardless of the author’s intentions, so often we readers end up trying to make those relationships something more.
It’s fun theorising, but with most of these characters I’d feel like it would taint something pure and beautiful by becoming romance.
It’s funny to me, because I have two friends who people used to pair me with. One was gay, one was straight. I wasn’t romantically interested in either. We had shared interests, we liked to do things together, we liked to travel together, but neither would have ever made me happy. The gay one because - well, he was gay and not interested in women 
and the straight one because he was very romantic and looking for “the one” and he was very needy. He needed a partner who’d be into the hobbies he was doing every weekend (running) and I’m a much more independent person who needs space and I’m not waking up early every damn Saturday to go run in the cold.
It didn’t make our friendship any less special or meaningful just because we weren’t romantically inclined.
I’m not sure if Ana is gay, straight or bi but I feel like she’s pegged Sebastien as either gay or uninterested. Probably because she notices that Sebastien doesn’t look at her like a guy looks at women. Damien might have a crush, but crushes go away - sometimes without even realising what they were. It might just be strong admiration for someone who’s everything you want to be - smart, indifferent, driven. He can’t be Sebastien but he can be Sebastien’s friend and bask in some of that glow.
I think they’re both good friendships that can remain as just that - friendships.
I’ll be a tiny bit disappointed if the thing with Oliver never blooms, but it won’t detract from the story in either direction. They might get too busy and let it snuff out or they might take tentative steps forward (like her telling him EVERYTHING about her past and getting his help when she’s at her most vulnerable!) and then have some comfort as they go into the turbulent plot ahead.
Either way, I’m looking forward with anticipation.
