Do you own a prodigy now, or have you been renting? If you already own a prodigy, you should probably stick with that to learn harness and footstraps. With the proper size sail, fin, and footstrap positions, the Prodigy is a fast and powerful board.
The Bic Core has more of a shortboard feel to it in higher winds but isn't as powerful in light winds as the Prodigy or Phantom 320 because of the shorter and rounder outline and smaller daggerboard. Also, when I rode one, a lot of water came up through the daggerboard slot, which I found annoying.
Probably the reason the Phantom 320 is heavier than the Bic Core 293D is because it has a larger, more powerful daggerboard, an adjustable mast track, multiple footstrap positions, and more length and volume. Even though those features add some weight, they increase the performance, especially the light wind performance.
So... If you want to progress your performance in both light and strong wind, I would go with the Phantom or stick with the Prodigy. If you want more of a shortboard feel in strong wind, I would go with the Bic Core 293D.