Once again, not all Baha'i. There never was a single solitary man. And Abraham is likely legend as well. Those stories do work as morality tales, but they tend to fail as history. Many Baha'i appear to accept this. There may not be different sects of Baha'i, but there are definitely different beliefs.
There is a big difference between believing that the morality tales told in the Old Testament are historical events and believing that Adam, Abraham and Noah actually existed. Baha'is differ on what they believe about the Old Testament, whether it is literal or allegorical, but we agree that these Prophets existed. However, just because they existed that does not mean they did 'everything' that was delineated in the Old Testament. For example, we do not believe that Adam was with Eve in the Garden of Eden, as we believe that was an allegorical story. We do not believe in the story of Noah's Arc and a great flood that flooded the whole earth either. Baha'u'llah delineated the significance of Noah's earthly mission in The Kitab-i-Iqan.
Deluge Myths, Noah’s Ark and the Renewal of Religion
A New Ark -- Why the Story of Noah Matters
Here are some Baha'i views of the Bible:
Introduction
Although Bahá'ís universally share a great respect for the Bible, and acknowledge its status as sacred literature, their individual views about its authoritative status range along the full spectrum of possibilities. At one end there are those who assume the uncritical evangelical or fundamentalist-Christian view that the Bible is wholly and indisputably the word of God. At the other end are Bahá'ís attracted to the liberal, scholarly conclusion that the Bible is no more than a product of complex historical and human forces. Between these extremes is the possibility that the Bible contains the Word of God, but only in a particular sense of the phrase 'Word of God' or in particular texts. I hope to show that a Bahá'í view must lie in this middle area, and can be defined to some degree.
Conclusion
The Bahá'í viewpoint proposed by this essay has been established as follows: The Bible is a reliable source of Divine guidance and salvation, and rightly regarded as a sacred and holy book. However, as a collection of the writings of independent and human authors, it is not necessarily historically accurate. Nor can the words of its writers, although inspired, be strictly defined as 'The Word of God' in the way the original words of Moses and Jesus could have been. Instead there is an area of continuing interest for Bahá'í scholars, possibly involving the creation of new categories for defining authoritative religious literature.
A Baháí View of the Bible