Hi there.
Overture can be a stand alone product and of course is an audio source it self. MCPAV9000 can only work through the AV9000 and probably with some other TVs but cannot be a stand alone product as it does not receive any comands directly or have a sound output.
It would be far better to combine your BV1 with an overture than MCPAV9000. Of course in my opinion!!!