Don't know too much about woolyboogers other than what I found at the first page of a quick Googling. Among some NSFW definitions that clearly would not apply, it included "A person who is one evolutionary step lower than a redneck." and "a booger (bogeyman) that is very hairy. This type of person usually has a lot of facial hair".
http://www.urbandictionary.com/define.php?term=wooly booger
http://neologisms.rice.edu/index.php?a=term&d=1&t=2030
So, no bigfoot here. No fringe subject, no bigfoot.
I have the impression shadow people are more recent bits of lore or urban folklore, legend, whatever. I believe I first heard about it in the late 80's, but I may be mistaken or just poorly informed. Sure, I bet someone can twist older myths and force-fit them in to shadow people babble, as footers do with bigfoot and myths from several parts of the world. Shadow people's decriptions are not similar to bigfoot's (again I bet one can find "intersections" between them, especially the paranormal bigfoot folks).
So, I really don't think there is or were, as you wrote,
"a deeply ingrained belief in the existence of "shadow people" or "woollyboogers", as they were called back then before the name bigfoot came into popular usage." I think its quite possible you built these connections quite later by confusing and blending some unrelated bits of lore. Its also possible that your memories of the accounts are not exact. Its been a long time since you heard them.
Another comment:
You wrote
"As far as the Nephilim are concerned, I'ld heard a new theory a couple of years ago that this is what people were calling the Neandertal when we co- existed together in Israel."
First, its not a theory. Its just a fantasy. Theories are based on facts, on evidence, they can be tested and used to build predictions.
Second, its a fantasy built over ignorance and data cherry-picking. Neanderthals were strong, more muscular than the average
H. sapiens, but they were also shorter.
Third, following the above line on ignarance and cherry-picking, Neanderthals were long gone by the Bronze Age, so the odds that the folks who compiled myths to build the OT or the people who created these myths or even the people who built the oldest cities in the Middle East having ever met a Neanderthal are very very very slim.
Fringe subjects such as bigfoot are built over ignorance, cherry-picking and distortions. I hope you can see that very little can be trusted from those sources.