I don't know if Nyx plans her consequences that far, but Layla is terrible at Spanish wish she probably wouldn't/shouldn't be with a Latino father and family.I'm pretty sure that incest is a no go in this game, so I don't see the MC having Alexis and Layla as stepsis. Even if you look in the history it makes no sense. Alexis mother got pregnat around the same time as MCs mother and they stayed in the same dorm at this time.
There was a small suspicion of this at certain point because the model used for their dad is quite similar from the back to the one used for the sports agent(and we never saw his face).
But apparently they are 2 different people and honestly "Navarro-Sports agent" should be the runaway favorite, everything about him "fits".
It would almost silly, an asspull, to go in a different route now.