In the mid-1960s, as hard to believe as it may be now, choosing to go into academic philosophy was not an imprudent career choice. There were lots of academic jobs in philosophy then.

Kant takes a free will to be a being or substance with the power to cause a state of the world (or a whole series of such states) spontaneously or from itself.

We can't coherently deny, or even decline to affirm, that we are free.

Marx is thought of as an implacable foe of capitalism. But go back and read the first section of the Communist Manifesto. Notice how it contains a paean of praise for the way capitalism and the bourgeoisie have both enriched the human powers of production and also enabled us to see with clear vision the nature of human society and human history.

Kant's aim was to develop a religion within the boundaries of mere reason (that is, reason unaided by special empirical revelation) and then to ask about existing ecclesiastical faith (especially about Christianity, and the Lutheran Christianity of his time and place) how this revealed faith must be interpreted if it is to be reconciled with reason, and even seen as a wider (though morally optional) extension of a religion of reason.

Kant certainly was sympathetic with the metaphysical tradition of rational theology that he criticized.

As Kant says, the contribution of any common laborer would be greater than that of the greatest philosopher unless the philosopher makes some contribution to establishing the rights of humanity.