I think I figured out why there are so many problems here
You say
Earth: The changing point of the matter.
Earth generally contains all elements including Fire, Water, Wood and Metal. (Mid/balance point of all five element)
I took Earth from Touhou's perspective while you took another one.
Life and Death is a constant, the transition is constant. Undead, poltergeist, etc are paranormal happenings, outside of the cycle.
EDIT: Also, she would be Eart element furthermore by the fact her body is the foundation of the seal on the Saigyou Ayakashi