Yes I'm sure that will work. You can already stream video to two CC from different apps on the same device so can't see why also streaming to an audio CC shouldn't work. Don't forget it's the CC doing the streaming, the phone is only being a controller.
What you can't do yet is stream the SAME content to multiple CC from the same app. That's what will be coming for the audio CC and hopefully with synchronisation to make a multi room system that won't echo.
What you probably still won't to able to do (I guess) is stream the same video to two CC from the same app. Though even now you could always use the same video content from two different apps to two CC if you really wanted to.