Please help me with the bracketed part:
By the time the style hit the masses – and twelve-year-olds in Sheboygan, Wisconsin, had begun wearing the teepee-like knits with flared jeans and chunky platform sneakers-the ladies who had first latched on to the trend [would rather have choked on a foie gras croquette than poked their heads through another poncho.]
The writer is hinting that Sheboygan, Wisconsin, is not exactly a hotbed of cutting-edge fashion. (It's not New York City or Paris, after all.) So once a particular fashion trend caught on out in the hinterlands, the people that started that trend abandoned it. They'd rather choke to death than to be caught wearing something that Joe Schmo in Wisconsin would wear.
(The reference to foie gras is just to emphasize how extremely posh and snobby these fashionistas are.)
Hello Ouisch, I wonder if it could mean that since ponchos were already fashionable in the 70's and they are now again in fashion, those who wore them back in the seventies wouldn't want to be seen in a poncho now. They'd rather be dead (the 'choking part') than be seen wearing a poncho. As the saying goes, if you wore it the first time round, you're too old to wear it the second time.
I perfectly understand your point of view and it probably is intended in that way.