In a sense you're correct. Enhancements don't change the abilities on the Hero for the purposes of abilities like Abner's Spear or Thaddeus. However, BfT is a Decrease SA and would definitely kill the EC regardless of whether SS kills a */1 Gold Hero. That I'm not so sure of, it depends on interpretation of the ruling, but at least one elder has interpreted it to mean that a side of the battle reaching 0 defense after its enhancements are factored in will result in Discard.