Hello, so I have my human model and I got 2 shape keys, one makes him shorter and the other makes him taller, is there a way to make both change the armature height as well?
As far as I know, the short answer is no. Changes to the armature will deform the mesh on top of the deform from the shapekey and it will be squashed/stretched twice as much as it should.
You’re probably best to animate the armature to change the height of the mesh, then create corrective shapekeys to fine tune the character mesh, if necessary.