Yolanda Montez is likely Courtney Whitmore's classmate and sidekick. They both attend Blue Valley High School and both seem to have ties to heroes from the past. In the comics, Yolanda is Wildcat. The following is from comic lore and is subject to change on the show.
Maria Montez and her sister are given experimental drugs by the mad gynecologist Dr. Benjamin Love while they are pregnant. Doctor Love keeps close tabs on most of his experiments, but loses track of the sisters when they travel to Mexico. In Mexico, Maria's daughter Yolanda is born on the same day her sister gives birth to Carcharo. Yolanda and her mother return to America to reunite with Mr. "Mauler" Montez. As a child, Yolanda manifests her superhuman powers, but is unaware of why she was born a mutant. She grows close to her godfather, Ted Grant, who is the mystery man Wildcat who operated during the 1940's. Years later, during the Crisis, Grant is crippled while saving a child. Yolanda assumes his identity to honor her godfather and the principles he represented.