On the question of endangered species, I also believe that Schmidtz would advocate for their protection. However, there do seem to be some issues associated with our current model of endangered species protection that I believe he would raise. Nonetheless, at least they are important to contemplate while we consider this notion of species egalitarianism.
First, why do we put more effort (aka time) into protecting some endangered species than others? I first think of the giant panda, which has become the poster-child for endangered species protection. But why? I would argue that it is because we find them extremely cute, thus making them profitable in zoos. We can also relate to them in some sense since their anatomy resembles ours in some way. Or, at least, it does more than an endangered snake or beetle that gets much less thought and attention.
We also need to consider how we preserve endangered species. I wonder if Schmidtz would be a fan of zoos. Probably not. But what about zoos who have endangered species and claim to be engaged in reproductive projects? The answer is unclear. I doubt that he would advocate for the objectification we engage in my placing sentient creatures in cages, no matter how spacious or seemingly resembling of their natural surroundings.
We also need to keep in mind Schmidtz' notion of self-respect.
All of the above relate to the idea of intrinsic vs. instrumental value. Are we really putting so much time and effort into saving endangered species because it is the virtuous thing to do? Or do we value individuals of endangered species because they give us happiness and the idea of their survival gives us happiness?