If you are going to be watching movies, you want to use the "VideoClock" option at Tools>Options>Video. So that means you can't Bitstream. Bitstreaming bypasses all of the JRiver audio processing. Also you probably want to use the DSP feature "Volume Leveling and maybe the Adaptive Volume, depending on your listening preferences.
When you bitstream you send the audio untouched to your AVR where the AVR then decodes it and turns it into PCM for playback (and the DTS-HD light, or whatever format light on your AVR turns on). If you are not Bitstreaming, the JRiver audio engine will process the audio and decode it into PCM then send it to your AVR. Your AVR will not try to decode PCM (no DTS-HD light comes on. On most AVRs the display will read something like "Multichannel PCM" or "PCM 7.1" or such). There is no redundancy.
Any room correction/bass management or similar setup that the AVR can do will still be used, or you could put the AVR in Direct Sound mode and have the room correction and sound management done in JRiver.