Mylene, Shadow and Volt were beaten... which only leaves Lync, Spectra and Mira. Yes, Mira. She challenged her brother, Keith - aka Spectra - in episode 21, but lost and is now an enemy of the Resistance. But later on, she rejoins them.
Yeah but they don't actually tell us much about the Vestals, like their home world or their existence. Other than the fact that the cards fell from the sky there too, not much is explained about them.