Just a little more information that I just uncovered.
It looks like a chip like this one: http://www.cirrus.com/en/products/cs4970xx_family.html can split the video and audio signals on the HDMI. But it maintains a digital format. After that another chip is needed to process the audio (I assume this is where it gets separated into individual channels but not 100% certain), and finally it goes through a chip to get decoded. The decoding is where the hang up is. I haven't found anything for sure but it seems you are supposed to have a license to decode HDMI audio. And most of the chips I could find to do such were sold in bulk only.
So maybe this is something that is beyond a DIY project simply because of the licensing and supply requirements. I read in one place that it was 15,000 dollars to purchase a license lol. Unless someone has more information on a cheap alternative method for decoding the audio. If that's the case I'll probably end buying something like that devices I linked on ebay and simply integrating it into my "unit". Either that or perhaps I will consider switching to a Linux based Carputer system in order to use a USB soundcard that has the outputs I want already on it... Lots of downsides to work around for that though, I'd lose Googles built into android voice recognition, google maps navigation, and a lot of other convenient for a car pc android apps. Or perhaps I'll just stay with my current audio set up and use a IoIo board or something to integrate with android and control the duplicated channel balances that way.