Recently I've been examining the Baha'i Faith after reading this from the Jehovah's Witness book 'Mankind's Search for God:
"The Baha’i faith is not a sect of Islam but is an offshoot of the Babi religion, a group in Persia (today Iran) that broke away from the Shiite branch of Islam in 1844. Their leader (Mirza Ali Mohammad of Shiraz) proclaimed himself the Bab (the Gate) and the Imam-Mahdi (rightly guided leader) from the line of Muhammad. He was executed in 1850. In 1863 Mirza Hoseyn Ali Nri declared himself to be ‘He whom God will make manifest’ whom the Bab had foretold. He also took the name Baha Ullah (Glory of God) and formed a new religion, the Baha’i faith.
One of the basic precepts of Baha’i is “that all the great religions of the world are divine in origin, that their basic principles are in complete harmony” and that they “differ only in the nonessential aspects of their doctrines.” They believe in the oneness of God, the soul’s immortality and the evolution of mankind. They reject the concept of angels, the Trinity, the reincarnation teachings of Hinduism, and man’s fall from perfection and subsequent ransom through the blood of Jesus Christ."
Jehovah's Witnesses do not think “that all the great religions of the world are divine in origin, that their basic principles are in complete harmony” and that they “differ only in the nonessential aspects of their doctrines.” Jehovah's Witnesses believe that every religion except theirs is part of "false religion" and will be destroyed at Armageddon.
Jehovah's Witnesses deny that Jesus was a manifestation of God, and they would utterly reject that anyone else, especially Muhammad, was a messenger from God.
Jehovah's Witnesses do not believe in the immortal soul or in the evolution of man.
Jehovah's Witnesses believe in angels (claiming Jesus was originally created as Michael the archangel).
Jehovah's Witnesses strongly believe in man's fall from perfection and that Jesus died to atone for the sin of Adam.
What elements do they have in common with the Baha'i Faith? Both denounce the concept of the Trinity and the reincarnation teachings of Hinduism. As to the "oneness of God," if by that it is meant there is only one God, then they would agree (except they say Jehovah is a big God and Jesus is a little god, but that's because they utterly fail to grasp the concept of the Trinity which declares that within the One Being of God subsist the three persons of the Father, the Son and the Holy Spirit.).
As far as the Witnesses are concerned, if you are not a faithful and obedient member of their organisation, you're going to die when Armageddon turns up - any decade now (although it's 98 years overdue according to their original predictions).
Personally, I think it would be an unholly alliance.
GT