The Third Amendment states ::

No Soldier shall, in time of peace be quartered in any house, without the consent of the Owner, nor in time of war, but in a manner to be prescribed by law.

Could Amazon, Apple, and Google voice recognition and home automation be used in violation of this?

While they are in the home voluntarily, bought and paid for with a purpose, I would say that the voluntary purpose is not to allow the government to listen in.

So, if the government is listening in on home automation ... is this a Third Amendment violation (... along with Fourth Amendment implications ...) ???