Thing about the 120 ohm K612 though, yes you'll need to crank the volume higher, but assuming it has the same/similar sensitivity then the amp wouldn't have to be able to pump more current into less voltage like the K702/Q701 that have 62 Ohms. So as long as the amp can be turned loud enough, then it's more likely to also have enough current and sound good.
Anyway, a Recon3D USB will take care of USB mic hookup (just buy a cheap lapel mic, like a Neweer 3-pack for $6), and then the K612 (will sound better with an amp, even a cheap FiiO E11 will allow the wife to adjust volume from her chair, but without an amp it will have less fatiguing highs than an unamped Q701). Cool thing about the Recon3D USB is that it's a nicely streamlined setup: you get mic+chat audio without plugging anything into a controller, so your controller is untethered, and the Recon3D USB comes with a nice flat-cable extension cord that resists tangles and is the only thing between your seat and the TV area while playing. Also, mic gain boost works, so she can make the mic louder if she has to talk quietly yet still be heard over game sounds. The only weaknesses IMO of the Recon3D is that it has the weakest amp of the console surround processors, and she won't be able to tune the chat:game volume balance. Neither was a big issue for me.
Other options: turtle beach is coming out with a new TAC unit, but I haven't had any hands-on time with it. Sennheiser also has a few wireless headphones that are supposed to be good with some built-in surround, but you'd have to figure out chat/mic. I already detailed my top recommendation first thing