That is something to think of. Not sure if the potion will give Snow White and Prince Charming an advantage–not unless Rumpelstiltskin goes for it. But then again, Regina did say that magic was unpredictable in the real world.
We don’t know for sure if she was born with magic–she might have had the potential, but never really the inclination to do so until Daniel died. Her mother seemed extremely powerful–either it was power that she was born with, or one that she managed to obtain somehow. I know a lot of people think the theory of Rumpelstiltskin giving Cora power is sound, but that seems to be a stretch. Why make someone else very powerful? He’d have competition.
But I do agree that Regina probably won’t have her powers back right away. After everything that she has done–after the extreme power struggle–Rumpelstiltskin is not going to want her to have power. She’s going to have to get it back.