The data transfer process happens at initial setup on the new phone, not when it's been in use after a while. So, you'll have to factory reset the 6A Also, google server back ups are partially encrypted with the phones credentials so it's not that big of a deal.

Ummmm, yeah... no thanks. I don't want the govt in my phone.

As I recall, you turn on the new phone and wait for the prompt. Been a while.

Are you able to select what you want to transfer -- such as only contacts, or only select media, etc., ..or does it DUMP everything over?

As I recall it does a dump. That's the beauty. Took less than five minutes. Googling shows possible selective restore.