Hokay... Fiddling around, I have managed to make the "Effect of Button" "Decrease Range" option for Encounter events work, but that only moves the sprite one step (the party does not move).
The above seems rather limited - I would rather do what you did in your animated GIFs (where the monsters step 3 steps toward the PC before combat)
I still cannot get the "auto approach" button to work in the combat event...