DJ, you’re putting too many eggs in one basket there.
What Moses supposedly brought down from the mountain were the Ten Commandments, written, so it’s said in Exodus, by the finger of God Himself. A bit more of the laws in Exodus were dictated by Him to Moses at that point.
The rest of the Torah, Genesis, all the laws in the other four books, were supposedly put together by Moses. On this view, God dictated the laws that comprise the majority of the Torah to him. Having “torah” mean both the Law and the five books that contain the Law kind of confuses the issue.
Moses supposedly wrote the narrative accounts accompanying the law collections, that comprise the rest of Exodus-Deuteronomy, except for the account of his death that closes out Deuteronomy, which Joshua wrote afterwards.
Modern scholarship believes it has identified four distinct traditions in the five-book collection, called the Yahwist (J), Elohist (E), Deuteronomic (D), and Priestly §. As may be expected, the most of Deuteronomy is D in origin. The parallel stories that occur throughout the Torah appear to be variants on traditional stories from the four sources, so that J tells of Yahweh parting the waters of the Red Sea, and E of God (Elohim) sending a strong wind that parted the waters.
Characteristics:
J = Great storyteller. Likes miracles. Calls God Yahweh throughout.
E = Also a good storyteller but not as good as J. Likes natural explanations of events. Calls God Elohim until Sinai, and then sporadically the rest of the way.
P = Hangup on genealogy and other detail, and on ritual aspects of the law. Provides the “frame story” for the other three traditions. Tends to call God Elohim until Sinai, Yahweh afterwards, nearly always the writer when “the Lord God” (Yahweh Elohim) is the describer for God.
D = Intensely moral focus, interest in Davidic history (shows up in Torah through focus on origins of Davidic line).
Oral tradition was supposedly collected and written down in Talmud. Not held as authoritative as Torah.
Yeah, I can see the potential for a big scam behind all this. But by accounts Yahweh tended to make himself obvious to people on and off throughout the history of Israel, not just to Moses. So the potential for a scam artist using the people’s gullibility to take over power is minimized.
Of course, you can throw out a lot of the theophanies and other stuff supportive of Moses telling the truth – but you’re left with a con artist with no scam backing him. If I tell you, send me $10,000 and I’ll intercede with God to make sure the (natural disaster of your choice) that hits your area doesn’t harm you, I’d better be darn sure that that natural disaster does in fact happen, or you’ll catch on awfully fast.)