Personally I'm not a fan of using more than two speakers in the same room for stereo listening, I think in mucks up the imaging. If you're going to get Pentas use them on their own, don't use them with either of your passive pairs. They're more than good enough to considerably outshine both.
(btw check all the Penta drivers for foam rot before buying, they can be easily replaced but any signs of imminent problems may help in establishing a price)
Generally speaking, you aren't learning much if your lips are moving.