The Aerial cc5 will mate fine with your atrias. Sure, it would be best with all aerial acoustics up front, but, you will be very pleased. There are boundary compensation and treble switches on the aerial to help with matching. The center channel provides 80% of the ht experience, so, having the aerial center will improve the overall sonic performance of your system.
As long as you calibrate the speakers to equal spl levels the difference in sensitivities will not matter as long as your amp can handle the most difficult load. In your case you will be fine as the Titan is a very capable amplifier.
As long as you calibrate the speakers to equal spl levels the difference in sensitivities will not matter as long as your amp can handle the most difficult load. In your case you will be fine as the Titan is a very capable amplifier.