Buddhism it seems to me has countless branches and divisions, and it is hard to talk about them all without a fair amount of study.
However, to differing degrees they all have the following in common, I would say: they are
gnostic traditions, in that through meditation and practice you can come to know and experience the true nature of the universe (particularly so in Zen Buddhism) - and they are
atheist, or perhaps more accurately
non-theistic - the forming of churches and the worshipping of deities is fiercely ruled out by Buddha.
Unfortunately, human nature being what it is, people have blurred that line a little, and in some places gods have been added. Not all Buddhists are atheists, but there are quite a few. The atheists are however
gnostic-atheists, or strong atheists - through direct experience and practice they claim to know god doesnt exist.
But in a direct parralel to atheists on the atheism vs agnostic thread, these buddhist atheists resolutely choose not answer the question of how creation came to be - just like modern physicists! Avoiding this question makes any statements they may make on theism absolutely redundant in my opinion - if you dont ask the question you're not allowed to give an answer!
The Buddha typically retained a pointed silence in regard to these sorts of questions, so much so that at one point he was directly asked how the universe and life came to be and
simply refused to answer. This refusal to answer should not be interpreted to imply ignorance-- there were competing theories at the time which the Buddha had undoubtedly heard of. Rather,
this non-response is usually understood to mean that the question is irrelevant to Buddhist theory. One does not need to know the origin of life, nor agree with Buddha's position on scientific topics, in order to become awakened. [again, the same argument of physicists]
Put another way, Buddhism is not an overly metaphysical religion. It is more oriented toward phenomenology rather than metaphysics, which has contributed to some questions as to whether Buddhism should be regarded as a religion at all.
http://en.wikipedia.org/wiki/Buddhism_and_evolution
Going back to the book in the OP, taking out those bits he doesnt like doesnt make his version of Buddhism agnostic - I havent read it so cant say for certain, but it is likely that it is still gnostic, as it encourages a direct knowledge of the universe through meditation, and probably follows the atheist position that runs through Buddhism, so it too will be gnostic-atheist.
If it drops that atheist position it has dropped so much as not to be called Buddhism anymore, I would suggest, and is just a piece of neo-gnostic, transcendental meditaiton, within a modern skeptical agnostic tradition - which I'm all for - but its nothing much to do with Buddhism anymore.