Interesting methods. Thanks for the info! Tasker is amazing. Using it on my phone at the moment to set up things when I get in/out of the car.
Where is the head unit on your build? Dont see it in the pic in post #1!
Just found an interesting video on a Sony HU that integretes with Android:
https://www.youtube.com/watch?v=a9zFDhy5Y3Y
Good luck with the build!