I was able to finally get two phones to work, somewhat?
One of the phones is connected by USB (main). The other is connected by Bluetooth.
I go into settings and pick the second phone to play media. This leaves the main phone for calls.
After that if I want to play music, podcast, etc. I go to sources and pick the (second) phone.
With two phones connected to Sync. I cannot do google voice commands or see google maps on the sync screen. Like i could with just one phone connected usb.