The news that Emma Roberts, the 21-year-old niece of Julia Roberts, has changed her mind about appearing in “Spring Breakers,” the latest project from Harmony Korine, the man behind “Trash Humpers,” doesn’t come as a tremendous surprise. What’s more important is that Vanessa Hudgens and Selena Gomez remain signed on, playing two of the movie’s four college co-eds, who knock over a restaurant to fund a beach run. (Roberts was to play “Candy, a Southern brunette who feeds off danger”; Korine’s wife Rachel will round off the quartet.)

Hudgens, of course, found fame in Disney’s “High School Musical” series and has since pursued grittier roles. Gomez got her start on “Barney and Friends,” later finding not-so-gritty movie and TV jobs. One wonders what “creative differences” they might have with Korine, whose movies have variously shown an H.I.V.-infected teen pursuing virgins (“Kids”); a boy wearing only underwear being hosed down in the cold by his father, who is played by Werner Herzog (“Julien Donkey-Boy”); and kids huffing glue and whipping dead cats (“Gummo”). Korine’s movies aren’t gritty so much as slimey. Brilliantly so, and beautifully shot, but still, not what you’d first imagine for Hudgens and Gomez.

Which fits exactly with Korine’s pop-shock approach — takes it, in fact, to the next level. “Spring Breakers” should seem all the more abject and absurd with America’s Juniors-section sweethearts leading the cast. Which, by the way, also includes gadabout hyphenate James Franco, as the drug dealer who recruits the ladies for a murder plot, and also raps. Franco’s ubiquity likewise helps check the boxes for “abject” and “absurd” (not to speak of the rapping). To dismiss Korine’s trash humping not only misses the point, it draws close the assumed limits of what our overexposed stars have to offer when they’re asked to stumble in the dark. Now, to find the next Candy …