Point 1 already contradicts beliefs of other religions. Why didn't the different manifestations get their "facts" straight before they told people what the afterlife was like? Would it have been that difficult to say "No, there is no reincarnation." And, "No, there is no bodily resurrection where the believers in Jesus go to Heaven and the non-believers go to hell." Why not until Baha'u'llah are these things made clear?
I think I already replied to this type of question, in another thread related. But I will reply again.
From a Bahai point of view, Recognition of a New Manifestation is a Test ordained by God in every dispensation. This is why, the Prophecies Regarding a New Revelation after for example Islam or Christianity has not been explicitly mentioned in Previous Holy Books. For instance, instead of writing in Quran that, another Messenger comes after Muhammad, He has said, a Day comes that 'the Dead is raised to Life'. Likewise, in Bible instead of saying another Messenger comes with a new Book, He has said 'Jesus returns'. In the same way, in older Religions such as Hinduism, instead of saying another Messenger comes with another Revelation, He has said, 'Krishna comes again at the End, and everyone will be born again'.
Now think about it. If God had said, 'Resurrection is not literal', 'reborn does not mean reincarnation', 'Jesus does not return literally, but someone else comes', then how would God tests and separates the Clean and unclean Hearts?
I think, you have a problem accepting, why should God test us? Or why He did not explicitly say, another Revelation comes, or why He kept it a secret with symbolic language. Right? What part of it does not make sense to you?
However notice that, in all the Books such as Quran, or Bible, God had already said that some of its verses are symbolic, and parables.
Do you see how people are tested? Look, there are worldly people who wish to see miracles, thus when they read, in Holy Books that God raises dead to life, they wishfully see it as a miracle. There are people who are not wishful to see Miracles, but they know, God means, reviving the Spiritually dead by a new revelation. Do you see how by these symbolic verses God separates that same people who came to Jesus and asked for Miracles!? They asked Him, show us a miracle. He said, only a wicked generation asks for a miracle. No miracle is given except the sign of the One who was eaten by fish, and came out on the third day. Now, think how that sign was shown. Was it other than rising Christ on the third Day? Then see how spiritual reality is the same, though they are expressed by different symbolic stories. It seems, the Author of the Book expects us to recognize its Truth, by seeing Signs in the symbolic verses. So, if that is the case, here is what we see; the Bab was Killed, on the third year, Bahaullah's Mission began, and after that He remains for Forty years. Sounds quite a parallel to story of Jesus, doesn't it?
Also think, what is the difference between the action of those who came to Jesus and asked for a Miracle, and if we also see the verses regarding rise of Jesus, or Resurrection as literal Miracles? So, how would God tests, those people who live after Jesus and wish for Miracles? Answer is: by the symbolic verses.