Because no human flesh was left alive, there were NO human family trees around when Adam was created.
The trees in the Garden of Eden were real trees that grew out of the GROUND. The fruit was to be eaten. Gen. 2:9
Lucifer now Satan is a spirit being that can enter flesh and blood. In this case the Serpent.
There is a spirit in animals and in this case the spirit in the serpent willingly allowed the spirit of Satan to come in. The spirit of the serpent could have rejected the spirit of satan; after all God was in the area.
The SEED of the serpent are baby serpents NOT human beings.
The Serpent being occupied by Satan's spirit, Lied to Eve.
Eve of her own free will obeyed the Serpent and thereby disobeyed God.
Satan is a fallen Angel. Originally Angels which are spirit beings that can materialise and dematerialise were created NOT TO HAVE SEX (Luke 20:35,36; Matt. 22:30; Mark 12:24,25.)as they potentially had eternal life. Because of rebellion Satan lost his light power and the power to materise and dematerialise. He is now a spirit being that can only enter another being on acceptance. If he repents of his rebellion things will change.
The topic of "Sacred Names" has only added to the confusion.