@Vorpal The kind of stuff you're describing here is the kind of thing the folks I know specifically look into. That's basically what I've been saying here: they're not trying to prove 'it's ghosts!' They're looking at accounts of hauntings and seeing: "Hey, what could be going on here?" They don't automatically rule out 'ghosts', but they also have a lot of different classifications under that heading that are, actually, pretty relevant.
A lot of what they talk about is, generally, that somehow some event is 'recorded' by the environment in some unknown fashion, and simply replayed like a recording. This has nothing whatsoever to do with magic, pixies, or even whether there's an afterlife or not. It's something most of these folks think is some kind of natural phenomena we simply don't grok yet.
There were, absolutely, a lot of the 'omg a shadow out of the corner of my eye moved!' 'creepy noises!' 'blinky lights!' etc. going on in that restaurant, for instance, but even as a kid I wrote off stuff like this because there's just too many normal things that could be that people love to scare themselves about.
Three things stood out about that place, though. Two? OMGWTFweird. One? I'm pretty sure someone could find an explanation for by digging into the walls similar to what you describe.
The last was something multiple folks experienced, myself included, multiple times. There was one room upstairs which would grow horribly cold -- and I mean cold enough we'd see our breath cold, even in the middle of summer -- in an instant, the lights would start to flicker, and everyone in the room would feel a weight on their chest, not too different from the feeling of that lead blanket someone drapes over you when they take dental x-rays, just heavier. Almost can't breathe heavier. And it'd stop as quickly as it started, generally lasting 1-3 minutes. That? Fucking terrifying as a kid, sure, but I'm pretty sure that could be explained.
The second is an OMGWTF, but definitely falls under the kind of events you're describing. The third floor of the place was closed to the public, and we'd always be up there during the open business hours. One night, we're meandering down to put in our dinner order (since they'd feed us up in yon attic-land) and we see a man in a suit starting to come up the stairs. We both see him. My friend says, "Hey, no one's allowed upstairs except the owner and family." And this guy, who is dressed like he's stuck in the 1920s (yes, I did know what a 1920s suit and hair and facial hair looked like as a kid, I have been a costume geek forevah) doesn't even seem to see us despite the fact that we're standing right there, too, and he just heads up the stairs right between us, and as we're just having to start to turn our heads to see where he's going? Gone. Nothing. No one. We ran all around the top floor looking for the intruder, and there's no one. She called her father to come up -- no one is there. And this guy? Just looked like a guy. Nothing remotely creepy about him save for his vanishing act and the retro chic. So while weird as fuck-all, there was nothing scary about that, really. That is the kind of thing that folks I know would likely consider potentially infrasound, as you're describing, or the 'something got imprinted on the environment here somehow' notion, which, again, is not something they think is outside the realm of what we may some day be able to explain.
The last one? Fuck, NO CLUE. Her father's office was a disaster. It was super clutter-land. She asked me to get some tape for some crafty crap we were doing, and I figure I'll go to what I assume is the supply closet rather than trying to find it on his desk, which we weren't supposed to touch. I open the supply closet, and she's going dead white while I'm asking, "WTF, this closet is empty, why don't you keep anything in it?" It was just a linen closet with full-width and depth shelves, and it would have made the desk less of a disaster. Instead of explaining why she was white as a dang sheet, she just picks up a pencil cup from the desk, and puts it in the closet. She closes the door. She opens the door. The pencil cup is now on a shelf higher than it was before, and the pencils are scattered on different shelves throughout the closet. I'm like... actually, "..." really does sum it up, so I gather up the pencils, put them back in the cup, put it on a different shelf -- and same thing, again. At which point she just looks at me uncomfortably and says, "We don't use this closet." She didn't exactly have to explain why, and... explaining would not have really explained shit.
That one? Zero fucking clue.
So, yeah, I am not mocking them for wondering wtf was going on in their place, or deciding to dub it 'haunted', ultimately, even if even I would explain it differently. It did accurately convey, 'hooooooooly crap, some weird shit goes down in this joint!' and they were seriously not kidding.