Each of these requirement turn out to be, indirectly at least, also moral obligations for Kant, and are discussed in the Metaphysics of Morals and in Religion. Both works depart from Leibniz-Wolffian views, though not radically.
Given that, insofar as we are rational, we must will to develop capacities, it is by this very fact irrational not to do so. What sort of objects does Kant have in mind here? Thus, the difference between a horse and a taxi driver is not that we may use one but not the other as a means of transportation.
Judgment is only possible if the mind can recognize the components in the diverse and disorganized data of sense that make those sensations an instance of a concept or concepts.
The goal of humanity is to reach a point where all interpersonal interactions are conducted in accordance with reason, and hence in accordance with the moral law this is the idea of a kingdom of ends described in 5b above.
Having a good will, in this sense, is compatible with having feelings and emotions of various kinds, and even with aiming to cultivate some of them in order to counteract desires and inclinations that tempt us to immorality. All means to an end have a merely conditional worth because they are valuable only for achieving something else.
But the Critique gives a far more modest and yet revolutionary account of a priori knowledge.
If I thought of my course of action as already determined ahead of time, then there would not really be any choice to make. It asserts that the right action is that action of all the alternatives available to the agent that has the best overall outcome.
So the very fact that I do deliberate about what actions I will take means that I am presupposing that my choice is real and hence that I am free.