Salam Brother, I appreciate you have done alot of research into this subject.
However, i would just like to say, IF the 666 phenomenom was important, do you not think that Allah SWT would have mentioned it in Quran or Hadith/Sunnah. Not one mention, which means its not from Allah or Abbrogated.
Also, the hadith you used is Daif (Weak) Although we do have tradition that there will be a beast from the earth that will be able to talk but it will be an animal, not human beast like in the book of revelations.
Again brother i would like to stress, please be careful because we have our Aqida which Allah SWT deemed enough for us , and Authentic. If there is no mention of those things in our Aqida, then we are only conjecturing.
As salamu alaikum brother