Not, mind you, as characters in the story. Like most of the people on the station, or off it, they are not appearing, which is indeed the main driver of the plot. But it's unlikely that neither child would think of them. And even if I stuck to the adult points of view, it's unlikely that neither child would ever mention the parents.
Best to make it a boarding school. Minimize questions that way. And I can even put them out of system, with its being such a prestigious school. But nothing will eliminate them.
Though I have mentioned that they look like the system's phenotype. May have to ship the parents out, or have a recent colony. Which would explain a great deal, come to think of it.