Los Espantapájaros are believed to be other active AAA wrestlers in disguise, and may only play these roles when their normal characters wouldn't fit the match.
Brandon is believed to be #2, and no one's sure who #1 and #3 are but Vangelis definitely played the role at one point and it would stand to reason the other would be Kevin. More than likely multiple wrestlers were put under the gimmick based on who was available at the time.
This type of gimmick, with a similar mask and outfit, was already used by Kahoz in 1997-1998. He was given the name Scarecrow and fought as single. And some months ago, an indipendent wrestler previously known as El Cortado lost the Espantapajaros incognita, maybe used only for that night, against Super Raton during an independent show.