As far as I could observe, "Daoists, Buddhists, pantheists, deep ecologists, and all those who have a mystical view of the naturalness and thus the interconnectedness of everything we perceive" have a pretty clear picture of "what our species amounts to from nature’s perspective" -- in human symbolism the term is "child."

My definition of humanism also widely differs from yours. I see humanism as derived from humanities that deal with knowledge of human in the first place and are held in their proper place by exact sciences. Hence, humanism, as I see it, only informs the areas of practical application (the larger the picture and precise the view, all the better). Or rather, it should, if it aspires to be called humanism.

Therefore, your question, "Are we slaves to nature’s evolution or bridges to an unnatural order?" is for me a false dichotomy because I see at least one more option -- our individual interfaces are basically automatons, indeed, but they are bridges to what we really are. That's the boon and the curse of meta-cognition.

¯\_(ツ)_/¯