Interesting idea, but I think it sets the audience up to expect that to be a focus of the movie when it ends up being minor subtext at best.
I wouldn’t say it’s a minor subtext, since the theme is shared across all of the main characters and the search for a missing person is the main plot of the movie. But I agree that any mention should be subtle so as to shift the focus of the theme without setting up a specific thematic payoff that doesn’t arrive.
Although, Rey’s main weakness is her desire for a parental figure which can never be truly fulfilled. If the audience also expected a tearful reunion of Rey and Finn with their respective parents, it would be that much more dramatic when it is revealed that such a reunion was never to be.