Nope. There's barely any nuclear power here now. Most plants were turned off after Fukushima. In fact I believe only 1 is online at the moment.

https://en.wikipedia.org/wiki/Nuclear_power_in_Japan

Ah, didn't know that. I guess they are mainly running on electricity from coal/oil/gas power plants, then.

Which is a lot more efficient than running off direct-drive petrol engines. There are reasons why e.g. diesel-electric locomotives are a thing.

All gasoline cars are running 100% on oil and that is never going to change. Electrical cars are using a mix of electricity sources, some not as good as others, but with each renewable energy source added to the grid, every electrical car, also the older ones, are getting a bit cleaner. Add to that the ability to steer the charging of the cars (at least partially) synced to grid load, they can help stabilizing the grid and make renewable sources easier to integrate.

Just like gasoline cars then. Gasoline cars use just as much electricity as EVs, as refining of oil to gasoline requires substantial amount of electricity.

With all the extra energy needs of gasoline cars for tankers, building and maintenance of gas stations, I think the world would need a lot less electricity production if everybody went electric rather than ICE.