The animations (unless blended or so) are ALWAYS absolute!
The problem that I was confronted with was the fact that the animation contained position (and rotation) for the root node (=game object itself):
Once I removed them, it behaved as expected.
Yes, you can play videos through GameMaker Studio 2, but you'll have to open and play the file yourself through extensions or DLLs.
Whilst there were built-in functions to open video files in previous GM versions, these have been marked as Obsolete Splash Functions in GMS1 and don't even appear in GMS2's Obsolete Functions list, meaning that they have been ...