Which is also a relatively recent thing, all things considered. If I remember correctly it was primarily WWII Germany that pioneered this approach, which was then quickly adopted by everyone else
I've heard this dichotomy in terms of military command presented in many different ages and different ways. It is primarily the difference between communicating the goals of an operation versus communicating how to achieve those goals. Most recently I've listened to accounts that it explains Russia operational failures in the invasion of Ukraine. I've also read analysis suggesting that it was a relevant difference in the battle of waterloo.
Sort of. The word to search the web for is Auftragstaktik. Here's the Wikipedia page on it: https://en.wikipedia.org/wiki/Mission-type_tactics
It was practiced by the Prussians during the Franco Prussian war. In WWI, it led to the small team grenade tactics, the Germans deployed to try to overcome trench warfare. It culminated with the blitzkrieg tactics of WWII.