1st I'll call Jehovah's witnesses accursed because denying that Jesus is Lord is a fundamental element of their faith, while believing Jesus is Lord is a fundamental element of true Christianity. We are all accursed, at enmity with God and children of wrath until we are born again of His Spirit. That's not my idea, but scriptures ' teaching.
2nd I appreciate the facts about the author of the NWT, but the JPS Tanaach is actually translated in the same fashion. Though it only includes the books of the Old Testament, the Hebrew scholars who translated it changed every messianic passage that points to a fulfillment in Jesus Christ in support of their rejection of Him. At least those authors were honest enough to place footnotes on these corruptions that usually state that the true translation is uncertain or unknown. As the Tanaach varies from the septuagint, an early Hebrew translation to Greek written some where between 100 and 300 years before Christ, it's safe to say that modern Jewish scholars don't trust the ancient Jewish scholars who wrote it.
With regard to the millennium there are things hidden from the angels that involve them and it probably isn't appropriate to discuss them as there are no explicit doctrines about it included in scripture, just hints.
Let me leave you with two verses and a question to simply consider.
“Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light; the stars will fall from heaven, and the powers of the heavens will be shaken. Matthew 24:29
Do you not know that we shall judge angels? How much more, things that pertain to this life? 1 Corinthians 6:3
How are men who have not lived like Angels qualified to judge them? Jesus said that in the resurrection we shall be like Angels and not given in marriage, but will we understand them, what motivates them, what the limitations of their authority was, and their concept of justice?