I might be the only one who feels this way, but I feel like since it would be too soon for Brionne to evolve, that it could evolve in an upcoming side story episode or be revealed to have evolved in a future series. I know it's pretty much guaranteed to evolve, seeing as Lana has its evolutions signature Z-Crystal, but it might not be during this series. If it does, it could be like May's Combusken and evolve in the second to last episode, or this time, in the last episode of the series.
If we consider the fact that the last two pokegirls have not had a return at this point, and only Iris got a special (poor Serena ;___;), I wouldn’t count on a future next-series return nor a special for anyone in Alola Squad either (thou I like the sound of Suiren going to meet Kasumi in a post-series special!). Thus, Suiren getting to use Ashirene/Primarium-Z is pretty much guaranteed before the end of this series. But that’s just how I see it. I totally can see Osyamari/Brionne evolving at the very, very end. XD But I hope to see it during the league!
