It’s the Mack Sennett girls, enjoying that nation-wide craze: standing barefoot on sharp rocks eating apples in hot wool suits. These were rather scandalous for the time, given the amount of gam revealed. They were scandalous in 1966, too – when they were miniskirts.
Context is everything. The presence of water gives you license to get slightly more naked; put these girls on the street, and the cop would have run the lot of 'em in for lewdness. Dis is Fifth Avenue, ladies, it ain't Minsky's. They couldn't have been more shocking if they'd had a cigarette in one hand and a condom in the other while they staffed a tongue-kissing booth for the Bolshevic Free Love Association. But put 'em on the rocks, and you get the bluenoses off your trail for a while.
The one in the stockings may be a trannie who snuck on the set; check out the sideburns. (The feet suggests she may be some sort of octopus trannie, at that.) Miss third-from-the-right just came from a hockey game, judging from her footwear. The fetching colleen on the right apparently couldn’t wait to get home for the monthly self-exam. That's the one you'd marry after a few "dates" with the black-clad Morticia Deville in the middle.