Warwick Avenue was originally called Warren Avenue when it was laid out on the Navarro tract in 1908. After the City of Los Angeles annexed this neighborhood in July 1915, streets that had the same names as those in L.A. had to be renamed to avoid conflicts. Since Boyle Heights already had a Warren Street, some civil engineer slightly altered this Warren to Warwick. That was in March 1916. As for who “Warren” was, my best guess is Warren Wilson, who in 1906 was listed as an incorporator of the Sierra Park Company, co-owners (with the Lifur family) of the Navarro tract. I have no further info on him.