... I would be curious to know if you came to a conclusion on how best to deal with audio for the A6000. ...
I haven't yet decided to acquire an a6000. If I were to get one, I would plan on getting an external sound recorder. If you do some web research, you'll find many available choices and lots of data and opinions. The model at the top of my list right now is the Marantz PMD661 Mk II.