Am I supposed to use the same path as for the Oppo for any HDMIi sources and just change the name?
Sort of. In the G61R all real HDMI sources (i.e. individual devices Oppo, Satellite, other DVD players) will be set to the same input (multichannel digital 1 or 2) because they are all coming down the same physical wire from the HD621 into the G61.
Then in the HD621 you need each of these real HDMI sources to have a different physical input and be configured within the HD621 as such.
As the HD621 and G61R are connected by COMMS, this will be co-ordinated so that the sound flows from the source device through the HD621 and G61R and to your speakers.
I hope this is what you meant and I am not barking up the wrong tree!