Regarding questions 5 and 6, an interesting discovery in Sinai, showed that "Jehovah" was at times accompanied by a wife / partner "Asherah", as late as the 8th century B.C. This seemingly sets a lower bound for the rise of monotheism in the peoples which will later create monotheistic Judaism.
The "lifestyle restrictions" have obviously evolved over time, with some fundamentals such as the calendar, sabbath observance, text in the phylacteries etc. still being debated until the first century A.C. That being said, archeological evidence shows that no pork bones were found in certain Canaanite towns at the beginning of the Iron age ~1200. B.C, so some of these traditions are indeed quite ancient.
Although different portions of the Torah were written far earlier, the canonization of the Torah is partially mentioned in the bible, when Josiah finds the book of deuteronomy (Kings 22). Thus the canonical pentateuch could not have existed before ~600 B.C at the very least.
On that note, it is clear from the text that torah learning was confined strictly to a class of scribes, and was not available to the general public. Even in the first centuries A.C, the talmud speaks about "Am Haaretz", seemingly the majority at the time, who were not familiar with the oral laws.
Of course, minor changes to the text were continually being made far far later, where rabbinical scholars in the middle ages still arguing which was of the many Torah scrolls in circulation across Europe and the middle east should be considered accurate.