Possible, but a little simplistic.
I doubt it.
That's a bit 20th century.
Fairly plausible as a minor reason.
Likely another contributor.
I think a lot of the theories floating about there are
way too Americentric. Countries don't invade other countries simply because of the invaded country's allies, if no open state of war exists. And don't give me any of that "PUTIN IS CRAAAAAAAZY" crap; he may be ruthless and power-hungry, but he's not that stupid nor that irrational. I think it's happening to cement Russia's already formidable power over former Soviet states: "If you resist, look what happens to you! Now give us your natural gas/oil/women." Georgia is a good testing ground for this because:
1) Georgia happened to pick some vaguely antagonistic maneuvers, giving a possible pretext.
2) Georgia did so around the Olympics, providing a distraction.
3) Georgia is a rather close ally of the West, allowing Russia to see a sort of "worst case scenario" for reaction.