Why hello there, guess I'll try to suggest things outside the obvious!
She's a ray of sunshine whom goes above and beyond to befriend absolutely anyone - I feel like these two would be fast friends. While she's a Bourke, she hangs out with everyone anyway and is all over the place, so that's not an issue. She's also an excellent people reader and oppressively selfless. She's about to take on her fifth year in Tally, making Alyona her senior.
My little jerk of a Sturt (or one of my Sturts, anyway), she has a bad attitude towards everyone and everything, most of the time completely unwarranted. An Irish girl with a very sharp tongue and an extensive profanity vocabulary, she's easily antagonizable. She could either be perceived as a bully, or have the very alien thing of 'making an actual friend' happen to her, depending on how you wish to go about it.
Not only a fellow fifth year and a Flinders, but also someone whom (secretly) wishes to pursue medicine! While this isn't a known fact, per se, it's very obvious she has a talent for that sort of thing, so perhaps they may bond over it. She is friendly and dislikes conflict in general, so enmity isn't to be expected. However, as per her own parents, Meadow might find it difficult to bring herself to hang out with Ona outside of Tally.
I have various others, but most aren't in Narrie in a permanent fashion/wouldn't have a particular reason to approach Ona (that I can see anyway), and my other Sturt wouldn't either. Regardless, check my splotter to see if you get any other ideas if you want~