[GOPJ]

...Manichaeism is so far removed from the what became the 'mainstream' of Christian theology that it is almost always referred to as if it's a separate religion, rather than a Christian heresy. That may be accurate, since it was essentially a synthesis of Christian, Persian, and Buddhist concepts.

What crossover beliefs are there with Buddhist?

[AntiGuv]

In particular, the reincarnation concepts of Manichaeism are thought to have been derived from Buddhist precept. Mani described Jesus, Zoroaster, and Buddha as prophets, and depicted himself as the last of the line with the most complete revelation (much as Mohammad would do later). Mani appears to have been raised in Persia as a Christian, or at least heavily influenced by Christians. Sometime after his "visions" began, he traveled on a spiritual journey to India, where he was evidently influenced by Buddhist thought. Manichaeism basically took Christian Gnostic metaphysics, including the concept of the Elect, and combined that with Persian dualism and Buddhist reincarnation/enlightenment.