Explain lack of heavy fog--and Russia's jumping up-and-down loudly yelling "fog!", when video clearly shows little.
What's "little" in terms of fog?
There is background light (the Sun) and ambient light in the video. Fog seen against a darker background (such as seen from a plane downwards) will appear thicker.
There is plenty of fog and the visibility seems to be around the claimed 400m. Also, as you pointed out yourself, the video was made a few hours after the crash. The presence or lack of fog in that flick is irrelevant. Fog can vanish within minutes.
Not some smoke-filled low light footage reporters shot hours later after the wreckage was burning fuel and PAH's (polyacrylic hydrocarbons) all day.
By then the firefighters did most of their job and the wind was blowing any smoke out of the way. Als, as I wrote earlier, another version of the same flick shows areas East and North of the crash and there is also fog. The breeze is coming from the North so if the fog was really smoke then little to none would have flown towards the North, against the wind. Unless Russian smoke is really a member of the KGB and was trained to fly against the wind.
Also, explain how Russia could not be behind it if they had the plane in their possession several months prior for overhaul.
That's easy. Not all people are smart just because they have brains.
The Russian service of the plane may raise questions and it may direct the investigation further, but at this point it proves precious nothing. I hope you understand the term "proof". There is none.