First, I will TRY not to be all pesky audiophily as I can see it would be looked at like recommending Felder or Minimax on one of the A/V forums I frequent... sorry.
Is no one advocating a phantom center concerned about the Re 20s and the fact they are recessed AND covered being able to coherently image the center channel, I can't see it not being unfocused and muddy? Plus the CV is a two way with a 8" woofer and a 1" tweeter and though I don't know the crossover point they beam like crazy. I would suggest something out of the current CV line for a center to at least have a shot at a similar timbre to the Re 20s.
I will also add a respectful "don't do it" about the Yamaha sub, the Polk and especially the BIC Tim mentioned are much better speakers. I would add the Velodyne VX-11, Definitive Technology Pro Sub 60 and Energy EW100. None of these are going to shake the foundations of the house or reach reference level LFE at 20hz BUT the bass that is there will be SIGNIFICANTLY better than the Yamaha which is a true one note wonder. For a tool analogy think of the Yamaha as Harbor Freight level.
Warning auiophile/golden ear blasphemy follows!! Regarding wire you are FINE. The only time wire makes an audible difference is with a mid-5 figures speakers made by names most people have never heard of and then only makes a difference when another audiophile is in your home and SEES the cabling and KNOWS you spent $1,000 plus on each set of wires, then and only then will the visiting audiophile wax poetic about the reactive component of capacitance and inductance and beam about the sweetness of the treble. The craziest thing I have ever seen in an actual home was a friend of mine who had a pair of Dynaudio Evidence Masters (over 80K a pair) connected to his amps with Audioquest Everest cabling, the cables were indeed pretty but should be at $9K a pop for a 6 ft pair, each additional FOOT was more than a Grizzly cabinet table saw! He wouldn't take the bet that he couldn't identify them compared to a set of 12 awg zip wire cables 8 out of 10 times. I ask you would any sane person spend 1500 times as much on something they they were not confident they could tell the difference 80% of the time??? Now I will bet you I can identify the Yamaha vs any of the sub $200 subwoofers I listed 99% of the time with music and 90% of the time with a movie as source material.
Oh and I do understand the preference for spending on video and not audio, my wife has appreciated the increase in every new display and projector I have brought into our house since we have been together, but not once has she been excited about the increase in audio quality. While she understands and can identify macro-blocking, compression artifacts etc, imaging, soundstage and the difference between a metal and silk tweeter are completely lost on her.
Bottom line if you are happy that is all that matters, audiophiles by and large just hate to see people buy "Harbor Freight" when "Grizzly" is just a few bucks more. Plus, people tend to replace sources, video displays and receivers rather frequently where a good set of speakers can last much of a lifetime. Finally, nobody mentioned Bose in the thread which kindly prevented me from having a stroke!