Well the thing is, we'll find out while playing at some point. It's not an endless mystery, it's get more frustrating to Ocean to keep dancing around it, whichever side of the fence it falls. Current facts are that we don't know if Nami's a Cyrus like Nika, we know Noji isn't a Cyrus, and we have the odd way they interact. We'll just keep picking at the knot until the reveal of the situation, but we won't discover the answer before time I don't think. Ocean loves reveals, after all every render is intended as a reveal, which is why the thing with Jenna makes it seem like there's a far more complicatd undercurrent to the situation.
Yeah, I mean, Ocean used the same model for teenage William as teenage Nika in old WiaB, but current WiaBthere's a different model. Nika being a Zane and being abandoned means jerk Willi won all of WiaB by being a jerk, because he abandons his sprogs, except Ayua, oh and all Ayua's sisters/cousins. Maybe it's completely and Oedipus thing, Nika was prophesied to topple his father's empire, so he was left on a mountainside in a cabin where Noji could find him and raise him....
Smells like gorgonzola? It's cheese.
I'd be interested to see that prude Noji thought she could rescue NIka and Nami from being corrupted by the Zane influence, which presumes they have some connection, whether the Cyrus's were competitors and the Zane's took them as wards maybe? Also cheese, so I'm hoping for a better explanation at some point.