Agreement is irrelevant. The Word is the Word or is it not?
"If God is not Spirit, than what is He, bound by the limitations of a physical body?"
God - specifically, the God of the Judeans - is bound by the limitations of what His adherrents wrote. He is their God and they are His Chosen, as the Book says.
Genesis was written during the Babylonian Exile, so "spirit" as you refer to simply was not a concept or issue in that mix. It simply didn't exist, period.
That notion, as well as that of soul along the same plane, one God, his opposition in the form of an evil entity, the afterlife, the Apocalypse, Paradise, Hell... those are all Zoroastrian, and started filtering in after the Iranians liberated the Jews from Babylon, and also later in Rome where numerous Zoroastrain and other Persian sects (Manecheism, Mithraism, etc) were widely practiced, hence Christianity bearing far more resemblance to it (and other Roman practiced faiths) than to Judaism.
There IS a reason Christianity isn't Judaism, and this is it.