Thats how I read it, some banks increase their gold holdings every year and possibly the ratio of their gold to currency issued also. So those countries are improving the quality of their money and its possible the market respects that and may raise the effective value
Personally, I don't see a lot of connection here
As long as you can't convert your paper money to physical gold in accordance with the ratio of gold reserves to amount of money in circulation (what you seem to be trying to convey in your post), it makes no difference. I mean, the government can pile up gold like there's no tomorrow, and the currency can still be weak, unstable, and highly inflationary due to insane monetary policies of the same government. If you could in fact redeem paper money for gold, that would technically mean a variety of gold standard implemented (which is prohibited by the IMF rules)
Russia and China have both been large buyers of gold in the last ten years and globally central banks have been net buyers of gold for a decade and I think that trend will continue because debt markets will likely reset or become illiquid
Because they know they don't stand a damn chance in the modern world on their own. Their economies will collapse if they lose their foreign markets