Starting with the shirts: The movie doesn’t explicitly say that they all belong to Fry’s Electronics employee Angel (Brandon Perea), but Bovaird says they were all meant to be stuff that OJ (Daniel Kaluuya) and Em (Keke Palmer) pulled from Angel’s closet as “a sort of shared uniform” for the main trio—Michael Wincott’s Antlers Holst, meanwhile, wears his all-black scarves and skirt to indicate that he isn’t really part of the team.
Bovaird says OJ’s Rage Against The Machine shirt (foreshadowing that the main trio is about to start fighting back at that point) came from a local flea market, while Em’s Jesus Lizard shirt (with a big cartoon wolf on the front) was meant to evoke a “really strong” image. Also, it cost $1,000 on eBay, which is wild.
At the end of the movie, though, OJ and Em transition to “‘80s-blockbuster costumes” like what you’d see in The Goonies or Back To The Future, and they were planned to be hand-me-downs from their own family. Em wears a soccer jersey that is meant to be something OJ used to wear, and OJ wears his father’s Scorpion King crew hoodie (which Bovaird notes is a meta joke about that movie’s famously bad CGI, given Nope’s plot and its themes about the danger of “taming” real predators).
Bovaird also shares some fun details with Vulture about Steven Yeun’s excellent UFO-themed Nudie suit, like the fact that the flowers surrounding the flying saucer shape are meant to look like Nope’s alien “unfurling.” As for that shoe in the Gordy’s Home flashback sequences (which both the camera and Yeun’s character seem to fixate on), Bovaird has some information about how it was designed and notes that Peele described it as a “jean shoe” in the script (a nod to Jean Jacket, the name given to the alien), but that’s all. Maybe that’s the point? OJ opines during the film that nobody knows what to call a “bad miracle,” but a shoe inexplicably balancing on one end while a chimp brutally attacks a few people is a pretty good summation of what he’s describing.
Go check out the Vulture piece for more details on the TMZ guy’s mirror helmet, the face veil, and an interesting note about one of the families prominently shown during the failed alien-baiting sequence.