Consider this:
The Early European ages, around the time of Christ, had druids that kept the tales, histories and lineages of the peoples. If they jacked with them at all, they were killed.
Jews were meticulous too. When copying, if someone messed up one page, judged by templates, they burned it and the ones touching it and started over, to keep it holy. The folks doing the copying could not read, they were artists. Thus they couldn't affect the topic and words any.
Atheists used to argue that we didn't have any hebrew writings, just septuagint and it had been copied and corrupted. THEN came the aramaic scripts of Nag Hamadhi and showed the scripture was right to the word, well, maybe one said a instead of the, but they were consistent, no changes occured.
As anally retentive as they were about keeping it holy, to imagine them rewriting it or changing it, is like expecting a bird to swim the rest of it's life, under water, Oh, and live a normal life span.
I've heard from some source that the time between the last Hebrew prophet and Christ's birth was about 400 years, but you say that Daniel was around 160BC. I'll have to do some research and learn more.
I wonder what kinda process the Jews went through to decide.
I've always thought since the Jews were commanded to teach their children the law, they would have to have copies and teach their children to read very early.