The Orions take 4 amplifier channels per speaker: one for the tweeter, one for the mid, and one for each 10" woofer. The Linkwitz base design is to drive these with a 60 Watt per channel amp. Linkwitz has a 12 channel design available.
Alternatively the two woofers in each speaker can be connected in parallel and then you only need a 6 channel amp. Linkwitz has a 6-channel, 180 watt per channel amp although he warns that 180 watts is enough to damage both the woofers and the tweeters if driven hard enough. Note: In parallel the woofers present a 2 ohm load to the amp.
The Outlaw amps should be able to drive the speakers although the manual does caution against driving 2 ohm loads at loud levels. I'd probably go with the 7125 to give plenty of headroom, but I will say I tend to be conservative. You'll need to add cross-overs somewhere.
I've looked at these designs a lot but never figured they'd be worth the money or effort. Also I've never run across anyone who had a pair. Do you have them? If so, how do they sound?