The Oppo 105 has 7.1 outputs and a volume control as well as independent speaker level adjustments. It also has 2 HDMI inputs, which it can process.
So it could be connected directly to your Rotel amp and viewing device, but it can't power speakers by itself. I tried this with the Oppo 103 and it ran fine for a while, but then started to exhibit low level hiss which I couldn't neutralize. It also made low level clicking noises when employing various functions. I swapped it out with my Oppo 95, which also has the 7.1 outputs but no inputs. It seemed to run my 7 channel amp fine, and it had been running an amp without issue in a 2 channel system.
So I'd do some more research, or maybe phone up Oppo directly and ask them what they would advise.