Your claim that the Gentile Times is bogus and that Dan 4 was only fulfilled in Neb is blatantly false. The evidence that Dan 4 has a major fulfillment is proved by the simple fact that the entire chapter is about God's Sovereignty and His Kingdom clearly something that lay beyond a mere human ruler. Further, Jesus clearly linked the tree dream with Jeusalem in his prophecy and the perspective of history in Luke 21:24.
Your opinion that the seventy years pertained to Babylon's dominion from 609 BCE until 539 BCE implies that the seventy years was Babylon's and not that of Judah. But such an interpretation shifts Judah's punishment of seventy years as stated by Jeremiah, Ezra, Daniel and Zecharian to that of Babylon but this is clearly impossible for Jeremiah clearly addressed Babylons's punishment along with the other foreign nations later in his prophecy.
The simple fact is that the seventy years applied to Judah alone and not to Babylon. Nowhere does the Bible state that Babylon was punished for seventy years but what it does state that Judah was to serve Babylon for seventy years thus Babylon's dominion over Judah was for that period of seventy years. All that can be said is the seventy years connected Judah and Babylon because Babylon was the instrument of punishment over Judah which lasted for seventy years.
I cannot answer your final question but I have received much postive feedback.