I'm pretty sure those things already existed before The Beatles. But it's safe to say the Fab 4 acted as a cultural amplifiers, so those things became accessible to global mass market.
This. The Beatles happened upon the right things at the right time and therefore cemented their place in the zeitgeist as the progenitors of a lot of stuff that they themselves probably wouldn't even take credit for. Taking psychedelic rock as an example: "Pet Sounds" predates "Sergeant Pepper's" but only one of these albums gets the graphic t-shirt and VH1/NPR/Rolling Stone retrospective treatment. This happens all the time and is largely a product of critics coalescing on narratives simple enough for them and their audience to reason about. It's easier to say, for instance, that Black Sabbath invented heavy metal because their name sounds a lot spookier than "Sir Lord Baltimore" or "Blue Cheer", not because they actually did it.
Is “Pet Sounds” generally considered “psychedelic rock”? It’s a good album to be sure but nothing on it sounds to my ears like anything in the same space as “Lucy in the Sky” or “For the Benefit of Mr. Kite” or “Fixing a Hole”.
I don’t think it is. However, the song Good Vibrations is in the psychedelic style, and came out before Sgt Peppers.