Our simple, obvious answer is yes. This falls right out of our observations on human action above; each person has within themselves an 'inner' veil, beyond which they cannot perceive, and therefore cannot predict their own inner workings. This presence of internal randomness proves that, from the perspective of a human observing themselves, they must have free will in their own eyes. Similarly, because other people are sources of randomness, it follows that they must have free will too.
This apparent obviousness does not entirely solve the mystery of free will, instead leading to two further refining questions:
From a 'higher' or more omniscient perspective, do humans still retain the capability of non-deterministic choice?
Does this mean that everything that's random has free will?
The fact that you do not have access to this perspective sort of renders the whole question moot. It falls into the category of things that are fun, but have no practical consequences. Still, we did come here to have fun, so let's take a crack at it.
Let's suppose that you were as close to omniscient as possible. Consider space-time as a 4-dimensional entity, where you are placed at some single point within it. This means that the "cone" of light traveling from where you are into the past is entirely known to you. Your knowledge cannot extend beyond that cone, because information cannot travel faster than the speed of light. Similarly, your knowledge of the future consists of the contents of the cone of light traveling away from you. You cannot know what is not in your cone; while you can surmise that e.g. the stars aren't about to explode in three minutes, this understanding is subject to uncertainty, however small.
We observe that in this higher perspective [1], you lack free will. Your own actions, and all their effects, exist within the future cone of light, and because you know its contents with certainty, it means that your own actions are completely pre-determined. Lack of choice altogether implies lack of free will.
[1]This state of existence, of omniscience coupled with impotence, can be described as sempiternal; it is not eternal, since it still has a dimension of time, but it does decidedly transcend time's apparent direction. In a peculiar paradox, this perspective is rooted at a particular point in space-time, meaning that sempiternity could potentially be a temporary, or even space-bound perspective. Some people report having glimpsed, in moments of altered consciousness, a perspective of the universe that extends until the end of time, a moment in which perfect pre-cognition is possible.
Definition Sempiternal (adj.):
Existing invariantly throughout time. Ex:"The present"
Definition Eternal (adj.):
Existing outside of the realm of time. Ex:"Numbers"
The re-introduction of free will breaks this perspective. If your impotent self suddenly gains a single choice, where you do not know which way you will choose, your understanding of the future fractures into two alternative possibilities, and the cone of uncertainty extends as a cone of light from the point of decision-making. As more options are introduced, the landscape of possible futures continues to shatter.
This leads us to a surprising conclusion [2]: uncertainty over the future is, at a minimum, the product of our own influence over it. And a surprising corallary: any perspective in which humans lack free will, lacks the power to influence human decisions. From the human perspective, humans have free will, and from the higher perspectives, human actions are inevitable.
[2]These are somewhat odd conclusions, and it may take a while to grasp them. As I have ruminated on them, they have however gotten clearer. Consider actions taken in the past: past actors obviously lack free will, but past actions also cannot be changed. Also see dominant theory. →
The understanding that the veil of randomness cloaks free will leads to another interesting interpretation. Because free will must necessarily lie behind the veil, does this mean that everything behind the veil has free will?
At first glance, it would seem as though the obvious answer is "no". If so, it would suggest that on a quantum level, where particles spontaneously and unpredictably pop into and out of existence all the time, the fabric of reality is somehow expressing free will. But what decisions are being made here? Where is the intent? Whose will does it reflect? I do not have these answers.
Still, it is not as outrageous as one may think to reach the conclusion that the answer is "yes". The most popular understanding of consciousness is that it is an emergent property of complex physical systems, however there is the alternative: that complex physical systems are the emergent property of consciousness. In this perspective, not only would it make sense that the fabric of the universe is capable of expressing free will, but it more or less requires that it does.
Furthermore, if we peer into the mechanics behind the function of the brain, it is at the quantum level that determinism breaks down; if humans do have free will, where else would it theoretically reside?
The principle of the conservation of energy falls apart at a quantum level; the spontaneous creation of particles from nothing requires the input of energy into the system. Normally, the physical explanation is that this is allowed supposing that that energy is removed soon enough, so that the imbalance isn't really "noticed". If free will acts through this boundary, it acts by injecting the system with small, temporary amounts of energy. As we observed when we watched hands emerge through this veil, the actual consequences of randomness is a function of the context in which it happens; the materialization of a particle in the atmosphere will quickly see its influence dampened by the background noise, however the materialization of a particle in the extremely sensitive context of a brain's cortext, if it leads to a change in human action, may have wide-reaching consequences. From this perspective, it could very well be that the entire fabric of the universe is constantly expressing free will, however it is only the portion of free will that happens to occur in the human brain that manifests itself as human action. When your awareness does not extend beyond the bounds of your body, it becomes easy to reach the erroneous conclusion that there is not consciousness happening beyond those bounds.