I have two guesses as to who Amarys' parents are. The first pair is Caitlin and Marshal because Marshal's elite 4 room is metalic and Caitlin uses Reuniculus. Amarys also uses Reuniculus on her team and she uses steel type pokemon, not only that but she pretty much acts as if she already knew how well a battle with elite 4 members would work, almost as if her parents are elite 4 members. The other pair I can think of is Burgh and Lenora being her parents. Amarys' orderly behavior could possibly be connected to the fact that Lenora is a museum curator and Lenora may have raised her to be like that and apparently Amarys is from Castelia City, the same place where Burgh is also from, and Amarys uses Scizor, which is a bug type pokemon and Burgh is a bug type gym leader. I think there's more evidence for Caitlin and Marshal to be her parents compared to Burgh and Lenora, but I think Burgh and Lenora are also a strong possibility for them to be her parents