In reply to Darwin's Theism. It seem's Charlie's beliefs evolved too. So what? The Theory of Evolution does not depend on any aspect of Darwin's life, character, or religious beliefs.
Incidentally, one could easily argue that Unitarians are not true Christians. There are essentials of the Christian faith which they reject outright.
Are you the ultimate arbiter of who is, and who isn't a Christian? They could say the same about you. And so could a spokesman from any other sect of Christians, or so-called Christian fundamentalists. Why would anyone care?
Also, read the footnotes in this article. They support its contentions.
Which, right or wrong, are irrelevent to any discussion of evolution.
Darwin's theology plays into his theory. It plays into what he actually saw and what he was wanting to see. It also reflects the theology of the vast number of evolutionists since. Evolution by natural processes (that is macro evolution) is a belief system accepted by faith. Nobody saw it. They say there is evidence, but biases play HEAVILY into that evidence. I'm intellectually honest enough to say that Creationism is a theory too accepted by faith. The contention that it is without evidence, however, is just willful ignorance.
As far as the Unitarians go, I'm not going to get into a big debate about them, but no I am not the ultimate arbiter. God's Word speaks for itself and will judge the living and the dead. Jesus made specific truth claims for himself, and the early church agreed. If you don't agree with those claims, you are not Christian, you are something else.