The first-person reality of free will is simply the experience of choosing. This is very subjectively real to us, like other aspects of consciousness - the qualia. We "discover" what we choose through consulting memory, values, motivations and beliefs, and this process of introspection is indeed what causes the choice, even though analysed from outside - the third person - we could describe the same process deterministically. It's not as if some external compulsion dictates the choice. Rather, the subjective experience of evaluating the choice, and the neurophysiological objective account are one and the same thing, seen from different perspectives. Therefore, the choice is real.
As for animals, yes they have at least some experience of choosing, I imagine, though the complexity of the process is less since the neocortex is much less developed. I don't think it makes any sense to talk about animal mortality, though maybe if I was a chimp I'd see that they have some rudimentary concept of guilt, compassion and empathy, but I don't know. I don't quite understand why you see the example of animals as an argument against my case here, and it suggests you misunderstand me. Or maybe I just misunderstand you.