Kant considers belief in God and immortality to be items of "faith" because he relates faith to the pursuit of ends - in this case, the highest good.

The Russian revolution did not occur until a generation after Marx's death. He was not involved with it, or with what came after it. His works do not describe post-capitalist society, and a fortiori they do not recommend any part of what the Soviet Union did.

I don't think Kant's approach to religion is any longer viable in its original form. But that does not mean it is simply wrong or that we cannot learn from it.

Some empirical feelings, such as sympathy, are indispensable parts of certain moral virtues.

We can never prove that we are free or integrate our freedom in any way into our objective conception of the causal order of nature.

Freedom is an unprovable but unavoidable presupposition, not an article of faith.

In fact people do not know enough about themselves and what is good for them to form a sufficiently definite conception of the general happiness (or whatever the end is) to establish definite rules for its pursuit.