Hullin 73: Impurity without Shechitah - Hypothetically Hypothetical Cases

Does a slaughtered animal that is a treyfa transmit impurity? It seems so. For a consecrated animal. At least at the rabbinic level of prohibition. Plus, the difference between a fetus, even with a protruding limb, as compared to other organs of the animal that might be detached from within and would lead to more complex prohibition -- it's a treyfa! Also, in the case of an animal that dies by other causes aside from kosher slaughtering, then what are the implications for the impurity of the animal, for a hanging limb, and more?