As to you PS:
this is a known bug (https://developer.blender.org/T58044) in 2.8.
Not so easy to fix, but there is a way to get it to work;
set Shape to Mesh and Source to Base as in the screenshot below.
Do not play the animation, but save your blend file, close Blender and open the .blend you just saved.
Now the hairs follow the Cube…
