Now that I'm not tired and can type coherently.
Aside from the bigfoot story from my uncle I have a second hand experience on the apparition side. My aunt and uncle lived in an old historic part of town. My great aunts & uncle lived across the street from them. The all had experiences with who they believed was the previous owner "haunting" the house. These two following events would happen very often.
My aunt & uncle would hear footsteps on the wooden porch and see a person's shadow go across the windows. Their dog would bark at it too. Thinking it was one of my great aunts/uncle coming over to visit they'd go to the door, but no one would be there. My mom thought they were full of crap until she experienced it for herself one day when she was over there.
My uncle would often work in the shop. At the end of the day he's shut down, turn everything off and lock up. A little while later he'd get a call from my great uncle (that lived across the street) that he forgot to turn the lights off. My uncle would check, see the lights still on, then go turn them off then lock back up again. The light switch was one of those old timey ones that you twisted and was pretty heavy to turn. Basically it wasn't one that would turn on/off without intention. Anyway, like an hour or so later my uncle would get another phone call.... "are you going to go turn your shop lights off?" Of course he'd be... "what are you talking about? I did turn them off." So he'd look and sure enough the lights would be back on. He'd go back and forth with this a time or two until the lights stayed off for the night.
I've wanted to believe in the bigfoot lore, but have always thought if they really existed why hasn't someone found credible biological remains? Maybe they have. I don't know anything about it. I've always been suspicious of the ubiquitous footprint plasters.
I don't know if the bigfoot of lore is real, but I do know it's 100% possible for creatures to go undiscovered even in well populated areas. It's funny to me that science is supposed to be open minded to possibilities and search for facts and truth with no bias. But scientists are some of the most closed minded people I know. 2 of the biggest examples of this from different fields....
#1 similar to bigfoot is the giant squid
Architeuthis dux; the one that the kraken legend is based on. For the longest time it was nothing that a fisherman's tale. No "true" biologist would ever give this any credit. And if you even thought the possibility of a giant squid existed you became a laughing stock in the scientific community. Lord forbid you actually tried to do a study/search.... might as well kiss your reputation and career goodbye. I guess the team that was made fun of got the last laugh when they found their proof.
#2 is another one from the ocean. Rogue waves. Since man started sailing the oceans stories of enormous rogue waves capsizing ships existed. Of course the scientific community didn't want to believe it. Similar to the giant squid, if you devoted any serious effort to studying the phenomena you might was well pack up your scientific career. No scientist could imagine how a random large wave could appear out of nowhere the disappear just as suddenly; even though the physics behind it is pretty simple and straight forward. Basically scientists called bullshit on anything that suggested rogue waves existed. It took a captain of an oil tanker (I think) to finally capture one on camera for the scientific community to consider they my be real.
And just in general there are many species that go undiscovered, some even going extinct without ever being known to exist. There have even been several species of great apes that have gone undiscovered for centuries until recently. Their elusive nature and smaller numbers kept them hidden for such a long time. Combining that with the scientific community's reluctance to consider the possibility they exist... I can 100% see this being the case with bigfoot going undiscovered. I can't say if there is such a species a bigfoot or not. What I do believe though is that similar to the example above, there's enough lore; which is likely based in some truth, that the possibility of their existence shouldn't be discredited.