Question 3:

The OT says that YHWH spoke to Moses and sent the plagues into Egypt. Jude says that Jesus IS YHWH.

No, he doesn't. You are reading stuff into the Bible passages that is not there.

Jude1:5I will therefore put you in remembrance, though ye once knew this, how that the Lord, having saved the people out of the land of Egypt, afterward destroyed them that believed not.

No, he doesn't say that God = Jesus - nothing like it.  Jude says 1. that: God (YHWH) saved the people out of Egypt - and 2. then God (YHWH) destroyed those that didn't believe. There are no two indivuals here, Jude refers to God (YHWH).