So far the discussion seems to limit the possibilities to two: Either
A) P-G knowingly filmed a human in a costume (the "Fake" scenario)
or
B) P-G filmed a genuine cryptid (the "Real" scenario)
People seem to be taking the view that, if "real," then everything in depicted in the film may must be real, and likewise for the "fake" scenario.
What about mixed scenarios?
Now to be sure, some we can exclude pretty easily. For example, the left half of the figure is 100% genuine bigfoot, while the right half is human in a costume.
But some mixed scenarios might be worthy of consideration.
Example 1) P-G unknowingly filmed a proto-cosplayer. Let us suppose for the sake of argument that a human with the unusual proportions cited can exist; that the costume was a labor of love for which this talented individual was willing to make extraordinary sacrifices that no professional makeup artist would consider, such as gluing hair directly to the skin; but that this outsider artiste was unwilling to admit in public that he or she wandered about in the wilderness dressed as an ape.
Evaluation: The only speculative science involved here is whether a person with the stated proportions can exist. Otherwise, the scenario is unlikely, but possible.
Example 2) There exists a natural force that can produce apparently real phenomena in response to strong emotions. P-G really wanted to film bigfoot, and the natural force obliged.
Evaluation: This hypothesis calls for the existence of a previously unknown, unprecedented, and paradigm-shaking physical process that potentially explains all fortean phenomena, makes hash out of religion, and in general has profound implications for humanity's place in the universe. Ockham's razor seems to weigh in against it, but hey, look at that explanatory power!
Other mixed scenarios may be possible, and potentially more useful.