Now that I take a closer look at those Revels, I would skip them. I had thought they would be some kind of on-wall analog to the Concerto free-standing speakers, but that is not the case, These are speakers that use 3" woofers. That is no real kind of woofer, and if you try to drive those speakers beyond a modest loudness level, they will not be happy, and neither will your ears.
The HTD speakers look like they could be good, and they are certain to have a hell of a lot more dynamic range than the Revels, but how would you install the Versa HTS1 as a center speaker? You can't easily install that horizontally in regular walls. That has to be installed vertically.
Is this sound system going to be paired up with a projector based system or a flat screen TV setup? Where, and how, do you intend to mount or install the center channel?