Skeleton jumps out of body

I am attempting this tutorial:

When I get to .fbx export I encounter the error: “Armature deformation will not work as expected, apply Scale to fix.”
Now, I’ve figured out how to do that, courtesy of this:

And when I apply the final step: Object>Transform>Geometry to Origin, I get this:

Also: the Tangent Space option in fbx export is greyed out. No matter what I do.