I agree with you on gold, cadmium, and bendalloy, but electrum stores determination. That's clearly a mental attribute. And yes, brass stores actual heat. So the breakdown for Feruchemy seems to be as follows:
Physical: Iron, Steel, Tin, Pewter, Bendalloy, Cadmium, Gold, Brass.
Cognitive: Zinc, Copper, Bronze, Electrum.
Spiritual: Aluminum, Duralumin, Chromium, Nicrosil.