Couple of points:
Spiderman has already been portrayed as Hispanic (in the series Spiderman 2099
pub. 1992) Created by Peter David and Rick Leonardi.
His secret alter ego is Miguel O'Hara, a brilliant geneticist living in New York in the year 2099 A.D. who is attempting to recreate the abilities of the original Spider-Man in other people and later suffers a related accident that causes half his DNA to be re-written with a spider's genetic code. O'Hara is the first Latino character to assume the identity of Spider-Man.
John Stewart (The first African-American Green Lantern, created by Dennis O'neil and Neal Adams, debuted in Vol 2 #87 in Dec. 1971/Jan1972.
...when artist Neal Adams came up with the idea of a substitute Green Lantern. The decision to make the character black resulted from a conversation between Adams and editor Julius Schwartz, in which Adams recounts saying that given the racial makeup of the world's population, "we ought to have a black Green Lantern, not because we’re liberals, but because it just makes sense."
John Stewart has become a major recurring character in the Green Lantern mythos within the DC Universe. He starred in the comic Green Lantern: Mosaic
, of which DC published 18 issues between June 1992 and November 1993. Additionally, he was the primary character in Green Lantern vol. 2
from issues #182 through #200, when Hal Jordan relinquished his place in the Green Lantern Corps (1984–1986). He continued to star in the book when the title changed to The Green Lantern Corps
from issue #201 to #224 (1986 - 1988). He was DC's first black superhero.
He was featured as one of the lead characters on the television cartoon Justice League
from 2001 until 2004. He continued to appear as a major character on the show's 2004–2006 sequel, Justice League Unlimited
. As of 2013, John Stewart is the primary character of the comic book series Green Lantern Corps