^^^^
Yes, there were a whole slew of "adventurer-explorer quartets" back then, with many published by DC, including these guys below--the Sea Devils (who debuted in 1960, a year before the FF). The Sea Devils quartet included a brainy leader, his blonde girlfriend, her blond kid brother and the leader's brawny buddy. Sound familiar?
above, Sea Devils....below, FF #1
One likely inspiration for the popularity/proliferation of adventurer-quartets was the 1954 TV show Rocky Jones, Space Ranger, which featured--you guessed it--a quartet. There was even a Rocky Jones comic, published by Charlton, in 1955.