I doubt that Nepal is number 8. The lowest point of Nepal is 59m above sea level, the lowest point of Mongolia 560m. Nepal is #2 for highest average elevation.
Where did you get the idea that the Caspian is the largest sea in the world? Googling it will tell you that the Philippine Sea is the largest but regardless the Mediterranean and Black Sea are right next to it. If you meant largest "lake" as it doesn't border an ocean, then that should answer your question of whether Kazakhstan should be landlocked, because it only borders a lake, not a sea.
Interestingly, looking at empires in terms of % of world population, then we get several Chinese empires, the Mongolian empire, and the Roman Empire all ahead of the British Empire. In terms of sheer numbers, though, Britain is far and away the biggest.
"Most densely populated (195)"