Bi-amping (passive in your case) will NOT give you 190 watts/channel up front. You're still only going to get whatever the amp can dish out depending on how many channels you're running. 5 channels driven and you're down to about 70 or so.
Here's the HT test results for the step up 2313
Two channels driven continuously into 8-ohm loads:
0.1% distortion at 126.8 watts
1% distortion at 152.1 watts
Five channels driven continuously into 8-ohm loads:
0.1% distortion at 77.7 watts
1% distortion at 90.8 watts
Seven channels driven continuously into 8-ohm loads:
0.1% distortion at 74.3 watts
1% distortion at 84.3 watts
Bi-amping the fronts from the AVR will result in the 7 channels driven output mode. So when things get crazy in the surrounds and center even for a brief moment you're only going to get about 75 watts/channel.
And for Arx, they do have a center channel the A2. Currently out of stock though. So you can run 3 towers across the front if your screen is wall mounted high enough or use one of the A1s. For the speakers the SPL at LP is directly related to how far you sit. So when watching movies withing the seating area you don't need to fill the entire 40x20' area.