What Did Moshe Know and When Did He Know It?

Thanks for the questions from the last posting. For those who didn't read them, they are important and will help to fit things together as we proceed.

So at the beginning of parshat Yitro, we are faced as readers with a bit of a dilemma simply trying to figure out when the scenario with Yitro visiting Moshe takes place. The chronological issue was provoked by the geographical issue, as we noted last time.

There is at least one more issue to give us pause, as well, and that is Yitro's advice to Moshe. We read in chapter 18 that Moshe gets up every day to act as judge for the people. Yitro suggests how Moshe can implement a judicial system which would be far more effective.

Is Yitro adding on to the Torah which Moshe already received at Sinai? Or is he anticipating something which will yet be given at Sinai?

As for Moshe judging the people: If the Torah has not yet been given, how does Moshe know how to judge the people?  Moshe says to Yitro:

שמות פרק יח (טז) כִּי יִהְיֶה לָהֶם דָּבָר בָּא אֵלַי וְשָׁפַטְתִּי בֵּין אִישׁ וּבֵין רֵעֵהוּ וְהוֹדַעְתִּי אֶת חֻקֵּי הָאֱלֹהִים וְאֶת תּוֹרֹתָיו:

Exodus Chapter 18 (16) When they have a thing (with legal implications), it comes to me and I judge between a man and his neighbor and I let them know the statutes of the Lord and His teachings.

How does Moshe know what the statutes and teachings of the Lord are if the Torah hasn't yet been given? While this question would seem to point to the understanding that this entire chapter must have taken place after the revelation at Sinai, there are other possibilities.

Where else in the Torah prior to this did we learn about justice?