This unless the story about the grandfather making it up is true. I've shocked older relatives with the stories I knew from before I was born. It was simple. I don't sleep well in strange places. I would curl up in a corner and after all the other cousins were asleep, the adults would start telling the deep secret stories. Some I did't understand till years later.
For your perusal...
The Hessdalen Valley is in a busy air corridor. The lights are landing lights from airplanes. The Taos Hum is technically unexplained, but the causes of other "mysterious" hums around the world have been decidedly mundane: tinnitus, animals, seismic events, industrial noises, etc. I don't know anything about 1) the aluminum wedge, 2) green-skinned people, or 3) the Pollock twins, but...
1) Out of Place Objects (or "OOParts") are frequently touted as amazing and then given to an actual expert who can explain it in a matter of minutes.
2) Argyria causes people to have bright blue skin. Another condition that causes green skin does not seem that strange to me.
3) Confirmation bias and the flaws of human memory could easily account for the unexplained or mysterious pieces of the twins' story.
With the Pollock twins, it's also quite possible that the parents told the younger girls things (or talked to each other about things) that the younger girls picked up on, and the adults forgot they'd told it to them or didn't realize they'd overheard. The younger girls could also be particularly clever enough to put together details (Sherlock-Holmes style) and make good guesses.
Last year my grandparents and most of their kids and grandkids were sitting around visiting when my grandfather told us a story from WWII. He spent a good part of the war serving in Italy. At one point one of his buddies had become chummy with a local family that lived in a farmhouse somewhere near the camp. The buddy got the family to throw a dinner party for him, my grandpa, and a few of their friends. They pulled out all the stops and it was a wonderful evening made all the more special by how removed they all were from the comforts of home. Resources were scarce for the Italian family too, and they'd asked each of the soldiers to contribute. The price, my grandfather said, had been well worth it. He ends the story by asking, "Do you know how much they charged us?"
I spoke up: "A pack of cigarettes."
"That's right!" he replied, visibly impressed. And then I noticed every other eye in the house on me. Everyone wanted to know how on earth I knew that. Grandpa never
talks about the war or about Korea. Never. I swore, and still swear, that he told that story a couple of years ago. I swear just about everybody in the room had been there the last time too. All 12-15 of them swear up and down they've never heard it before. I can't believe they don't remember it since it is the only story he's ever told us about the war. They say they couldn't possibly have heard it before because they would never forget him breaking his silence. It's a stalemate.