Auld Soul
Indeed !Daniel was referring to Jeremiah's predictions about the seventy years that these applied not to Babylon as you claim but for Judah. Jeremiah 25;12 inroduces the time element 'fulfilling of the seventy years' of Judah whenc e Babylon would receive her judgement of desolation. I agree with you Daniel knew both the beginning and the end of the seventy years and I would add that so too, Jeremiah.
I disagree with you that there is a neutral aspect regarding the devastations of Jerusalem having no past-present or future aspect. The paper by Applegate on an exegesis of this verse indicates that there is a continuative aspect from the time of Daniel's prayer. I propose that such aspect is proven by the expression 'fulfilling'.
In regard to Zechariah you agree with me and thos e celebrated WT scholars that the seventy years were a past period which differes from the Jonsson/apostate view. Welcome aboard.
Jeremiah clearly indicated that Jerusalem and Judah were to be devastated in order for the land to keep its sabbaths. Covenant and sabbath theology makes this a matter of fact. Jeremiah 27:16 shows at the time of Jeremiah uttering that prophecy there was apossibility that Jehoivah's judgement could be reduced by an exile alone but they ignored Jeremiah's pleadings and brought upon them a much heavier burden that is the complete desolation of the land for seventy years.
scholar JW