All I know is an atheist and Christian are black and white. An atheist by definition is one who claims God does not exist while a Christian says God does exist and his name is Jesus Christ. Their is no such thing as a Christian-atheist, they are polar opposites. So I don't understand why you are attempting to blur the two, if that is what you are attempting.
There are some who claim to be agnostic theists and some who claim to be agnostic atheists.
Agnosticism deals with knowledge while theism deals with belief. The two are not mutually
exclusive. Furthermore, if you actually claim to know God exists then what's the point of faith?
You don't need faith anymore when you know something is true.