The excellent observations made in your post indicate why bigfoot is studied by cryptozoologists.
I too am very, very curious about these creatures. Too many have been sighted by reputable people with no reason to lie to not believe that there is not something out there...whether it can be proven or not.
"So the question might be, is it of a corporeal nature or not? Now that is binary thinking.... so can it be both? Are there things in this world that are bodily, spirt and then both?"
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"whether it can be proven or not."
You mention something very important that deals with empiricism. Science, empiricism, can't really speak to all things in this vast world. It is limited.