check your materials,
example for the sony-hedghog:
parts of its mesh are asigned to the first material (red-default-called-one)
and those parts are not uv-mapped to image, they are outside the image.
But i think this is wanted, hands should be white-like-gloves.
Tab into edit-mode for the sonyhedg
and press key “a” (maybe twice) so NO vertices are selected in edit-mode
Then select the first material, the default-red-one,
and press "select"button to select all vertices attached to this material.
You will notice the hand-gloves will be selected now,
you have to delete/remove those from the material to get them free.
!!! btw. there is no button to remove selected vertices from a material !!!
you have to create a new material and attach those vertices to this new material
and then delete the material to make all free again.
But! if this first default-red-1 material is not used for the sony-hedghog,
then simple delete this material to free the assigned vertices.