Was the period from Nehemiah's decree to Jesus' triumphal entry fulfilled exactly to the day?
Yes. Daniel's prophecy was based on the decree given to Nehemiah to rebuild Jerusalem's city wall, not Ezra's temple work. From that date, approximately April 14, 445 B.C., until Christ's triumphal entry into Jerusalem on Palm Sunday, the period was fulfilled to the exact day.
Les emphasizes that the decree under Nehemiah was to rebuild the city wall, not the temple; Ezra was the one who rebuilt the temple. The prophecy in Daniel 9 is based on Nehemiah's return, not Ezra's. He notes archaeologists have found the decree dated April 14, something like 445 B.C., when Nehemiah got permission to come back and rebuild the city wall. From that date until Christ came into Jerusalem on what we call the triumphal entry, Palm Sunday, it was fulfilled to the exact day. Les then transitions to Daniel, who writes from Babylon while in captivity, and introduces Daniel historically and prophetically.