For most young gymnasts, meeting Simone Biles is a “once-in-a-lifetime” dream. For two sisters from Cross Lanes, that dream came with a side of professional modeling and a personal coaching session.

Few gymnasts are instantly recognizable as Simone Biles, the most decorated American athlete in her sport’s history. With over 40 Olympic and World Championship medals, Biles is dubbed the “GOAT” ...