Sorry I misread the original question. Yes, you remain in F-2 status. F-2 are admitted for D/S on their I-94, which means it lasts indefinitely, as long as the F-1 is attending school in good standing and you have a valid I-20. The visa's expiration is irrelevant.Thanks for clarifying the difference between status and visa.
From that, I suppose I can assume that in the event of my application for H-1B is unsuccessful, my F-2 status (and also my F-2 visa stamp obtained upon entry previously) will still stand as it is until 2020?