the "Father of spirits" reference comes from Hebrews 12 but LDS usage fails to notice the surrounding context. Verse 8 reads, "If you are left without discipline, in which all have participated, then you are illegitimate children and not sons."
So given that Mormons want to take verse 9 ultra-literally, we have to ask: Are there illegitimate spirit children here on earth? Did God cheat on his sealed wive(s) in heaven and sleep with another God's wife, thus having illegitimate spirit children, some of whom have been sent to earth, never to be disciplined? The whole point of the p***age is that "God is treating you as sons" (v. 7), i.e. by discipline. The language is that of metaphor. If not, Mormons should be consistent and admit God the Father had an affair and that he had spirit children out of wedlock.