I believe life is predominantly about exercising our free will. I think there is a degree of predisposition, but not predetermination or predestination.
To use an analogy, imagine we are each cross-country walkers, and all we do in life is walk. We may be wired (predisposed) to walk north, and that's what feels most comfortable to us, most inherent, but we have the free will to alter the course at any moment and walk in another direction.
We start out with a direction in life, but by no means do we have to keep it. So I believe both are present, but free will has greater dominance than predisposition. It 'trumps' predisposition, so to speak.
I think the purpose of life is growth and learning, so that is the reason for all situations. Having said that, I think everything does happen for a reason but that reason is neither static nor singular. A situation has the potential to mean a variety of things to one person depending on how we decide to let it impact us. I don't believe events happen randomly. There are probably multiple layers of meaning to each situation. We probably tend to grasp a few of them, based on our current level of understanding. So it's probably both. I don't think we're fully pawns nor do I think we're meaningless dust particles floating around. I think trying to ascertain ALL meaning is like a fish trying to figure out why someone is tapping on the fish-tank. Most people simply don't have the perspective. Much like the difference in view while being at the base of the mountain versus partway to the peak. However, I think there is reason and purpose to being alive, and we make sense of what we can while we're alive (hopefully). Hopefully, the more consciously we live, the more we evolve through this process, and expand our perspective and ability to 'see more' to each situation and consider different meanings. The greater this ability, the more likely it is that we'll be able to make life go smoothly for us, climb out of ditches if we've been thrown in them (ex. as children), or climb out of existing potholes. I.e. The more effectively we'll be able to exercise our free will to meet our desired outcomes, regardless of predisposition.