This is the best one of the three as concerning of focus. It still shows soft on the image. I am not to intend to discourage you about this lens! As a matter of fact, I was once considering to buy this Tamron to replace my broken Sigma 50-500mm lens which failed with the focusing motor after 5 years of moderate use! I have been keeping my attention of the user reports and sample images for this lens. So far I have found out the image taken with this lens at the long end (600mm) were soft as showing from your pictures here. It may be better if using aperture f8 instead of wide open at f6.3. You know this is a slow lens and needs plenty of light to get a good result.
The noise in the picture was the artifact of the result of the high ISO noise reduction effect from your camera, especially in the out of focus area.
That's why I have a second thought to get a prime 300mm lens coupling with a tele-converter instead of a zoom. I belief that a prime is always better than a zoom.

It is only my own thought, just enjoy what you love! Keep shooting! :) :) :)