Look on the general forum section for "Speakers" and you'll find a posting about quality regarding RBH. They sent a buyer speakers which appeared to be used and had corroded terminals right out of the box. I'd avoid them for that alone. Chane is better with reputation, I've never heard them.
I don't think you can use a tall floor standing speaker as a center as long as you have a solid traditional TV. They CAN be used with an acoustically transparent drop-down screen though. Pretty certain you can't buy a single one though. I'd just get a Q600c.
That said, I have a biased opinion because I own KEF R series and my son owns a Q500/Q200c/Q800ds/iQ10 7.1 surround system with an SVS PB2000 sub. In his 16' x 25' x 8.5' room, it's STUNNING for home theater and gaming that he & his fiancé use it for. He has a pair of Q300's in their master bedroom 2-channel system, and they're terrific.
KEF R500, R200C, R100, SVS SB2000 sub, NAD T758 receiver, Pro-Ject RPM1 TT w/ Ortofon 2M Red, Bluesound Vault2, Sony BDP-S480 BlueRay player, Samsung UN55JU6500F 4K LED TV, KEF M500 headphones, Sony CDP-CE500 CD changer.