I do agree that Romero's zombie hordes tend to have a good representation of Zombies of Color.  But, I see that as supporting my case that zombies represent the racial Other.  If anything, I think that the presence of Whites in the zombie horde would contradict my argument.  But, I think there are a number of reasons, practical and symbolic, why even Romero's hordes have plenty of zombified White people.  First off, I think that the racialization of actors playing zombies is less symbolically important than the in-story characteristics of the monsters themselves.  For example, in the Kate Beckinsdale race-war parable, Underworld, both the Vampires and the Lycans have one token Black member -- but to me, that's much less important to my interpretation than the overwhelming symbolic characterizations of the Vampires as White aristocrats and the Lycans as the formerly enslaved, Black resistance fighters.  Which leads me to my second point:  Practically speaking, I think that institutional White Supremacy in Hollywood means that any large group of extras would have plenty of White folks in it (unless the script explicitly called for, say, a group of non-White people).  And third, symbolically, because some people DO look more at who's cast in a role than at the characteristics of that role, I think that casting a zombie horde with entirely non-White performers might be more terrifying to many White audience-members on one level, it would also undermine some of the threat of pollution or conversion.  If a non-White zombie horde merely killed White characters, then the fear of racial pollution would be lost.  Part of the terror of zombies is the fear of losing one's personal, familial, romantic, and racial loyalties to an overwhelming pollution by the Other.  And, what with historical and contemporary fears of racial pollution of both individual bodies (e.g., by sexual relationships, whether procreative or not) and of the body politic (e.g., via immigration, miscegenation, or what conservative theorist Samuel Huntington called the Mexican "reconquista"* of land the U.S. forcibly took from Mexico), the fear of pollution seems to be a, ehrm...  "vital" part of the terror and fascination with zombies.

*Also, notably, Huntington's idea of a Mexican "reconquista" of the U.S., which is hugely popular among Right Wing groups like the Minutemen and other anti-immigrant groups, actually inverts the original use of the term.  My understanding is that, originally, the "reconquista" referred to Catholic Spain, several hundred years ago, "reconquering" European land that had been conquered by Muslims.

As for Resident Evil, I sometimes try to imagine how a producer might pitch a movie by alluding to three other movies or less.  For me, I'd pitch Resident Evil as Aliens meets "Night of the Living Dead.  Replace Resident Evil's zombies with Aliens' xenomorphs and you're basically back to Aliens -- a survival horror movie in which a small band of low level military folks realize that the military-industrial-congressional complex is much more powerful and nefarious than they realized, and that it may, through its greed, be the death of humanity.  But, in both cases, the MICC has trifled with the literal, biological equivalent of a rapacious corporation, respectively, zombies and xenomorphs.  Which, perhaps also relates to what Melanie Kaye/Kantrowitz has referred to as the paranoid "squeeze play" story that many White Supremacist ideologies have historically sold or told to working class White people -- that they're squeezed between powerful elites (generally scapegoats like Jews or East Asians, standing in for overwhelmingly White and Protestant-run and -flavored corporations) and underclass hordes (generally scapegoats like Black folks or Latin@ immigrants).  So, in both cases, the heros are facing off against corporations from above and zombies or aliens from below.

So, yes, I think that zombies generally stand in for those aspects of Whiteness about which people are uncomfortable and want to project onto an other -- regardless of the race of the actors cast to play them.  In your post, you note this too -- as Romero put into the mouth of one of his characters, "They're us."

I will, also, give Romero credit over most other tellers of derivative zombie stories -- Romero comes closer to recognizing that "they" are "us," than most of them.  In the more derivative stories, "they" are much less like us and much less sympathetic as monsters.  Romero, after all, was the one who posited in Land of the Dead that perhaps working class humans (symbolizing working class Whites) might be better served by casting their lots with zombies (symbolizing the racial Other underclass) than with the rapacious and callous upper-class Whites.  This is, after all, a basic anti-racist message -- that poor Whites should favor class solidarity with other poor people, regardless of race, over racial solidarity with upper-class Whites.  In contrast, derivative B-movies like Flight of the Living Dead are a very transparent Orientalist interpretation of 9/11 fears and stories -- it's a story about a group of people who sneak onto a plane and threaten to crash the plane into a crowded city, magnifying their power.  Of course, Flight of the Living Dead is talking about zombies, not racialized terrorists.  Not subtle.

I definitely appreciate and respect your points about citizenship and reproduction.  With a bit of symbolic unpacking, I think that White women might also be good allies against the oppressive symbolism of many zombie stories -- because, as you point out, racism and sexism are intertwined and mutually reinforcing.  I'm reminded of past ways that White Supremacist Patriarchy has used the imagined threat of Brown Hordes (generally of men) to control Women of Color, Men of Color and White women.  I'm thinking, for example, of then-President Teddy Roosevelt's admonition to White women, in the early 1900s, that they were committing "race suicide" by having abortions and by not producing enough White children -- because in those ways, the Brown people of the world would out-reproduce and overwhelm White society.  So, when White women today hear stories about Brown people "overwhelming" White society, I think alarm bells should go off.  Because such stories, when deployed, often imply that White women should be valued primarily for their (unpaid) labor reproducing the White race over all else.

First off, I definitely agree with your read of the Borg as space zombies.  I find the Borg particularly interesting, in part, because I also read them as Rodenberry's Capitalist fear of Communism (Rodenberry did, after all, believe that militarized "enterprise" would carry us into a utopian future.).  On one hand, I don't think of Soviets as "Orientals."  But, on another hand, U.S. representations of Soviets varied over time, with Soviets "Oriental-ness" rising or falling in time with whether we were opposing them or allying with them.  When we were allied, the Soviets tended to be represented as Whiter; when we were opposed, they were more Orientalized.  And now, with the collapse of the USSR and China's re-emerging power, the Borg seem even more Orientalist, standing in for fears about Chinese Communism.

As an aside, I also read the Reavers of Firefly/ Serenity as space-zombies.  But, in an intriguing twist, Joss Wheadon suggested that the Reavers were actually betrayed (ostensibly White) colonists, who were seeking revenge against their brutal colonial regime.  So, while I originally read Serenity as an anti-imperial answer to the question, "Why do they hate us?" (answer: because a "Pax" Romana would make some people rebel violently and relentlessly), I now think of Serenity as a story about how White Supremacist imperialism itself is the "pax" that poisoned underclass White folks -- and while most White people would be cowed into a deathlike submission, some would go completely apeshit, becoming indiscriminately violent (rather than striking against the source of their pains: upper-class White imperialism).  Unfortunately, Wheadon's explanation of the Reavers also implies that there were no indigenous people on the lands where the Alliance sent colonists.  But then, Wheadon's read, like Romero, acknowledges that the stories "we" tell are about "us," even when we say that the monsters are some Other group.  

And speaking of the ways that racism and classism or imperialism are bound up in each other, I appreciate your point about the White underclass "mutant" monsters from The Hills Have Eyes.  I think there's been a resurgence of interest in stories about middle-class Whites who're terrorized and violated by underclass Whites.  (I'm thinking here of franchises like The Hills Have Eyes, Texas Chainsaw Massacre, and Rob Zombie's films.)  I think that the relatedness of racism and classism in these movies may be generally under-examined.  Because while the "monsters" in these films are racialized as White people, they're explicitly poor White people.  And I believe that classism and racism are mutually constituting.  Over the U.S.'s history, many European groups have been re-racialized to be included in Whiteness -- a Whiteness that is distinctly Anglo.  I'm thinking here, for example, of the Irish, Scots, Germans, and Italians.  But, I think that the prior racializations of these now-White groups still persists -- and that those ideas become most obvious when we're talking about poor White people.  I think that, in the U.S., despite myths of a "classless society," social class is seen in racial terms.  Britney Spears, despite her wealth, is still castigated as "trailer trash," because of her perceived unwillingness or inability to behave like a "proper" upper-class White woman (in which "proper" implies old money tastes and manners -- which are defined in large part by Anglo norms -- not Irish norms, not German norms, or so forth.)  In some ways, money does Whiten -- or rather, perhaps lack of money makes Whitening seem less convincing -- and then the monstrous racializations of the past become more obvious.  Plus, because of class segregation, poor Whites have been more likely to live in close proximity to (disproportionately poor) People of Color than wealthy Whites.  So, in this oppressive logic, to be poor and White is to be one step closer to being poor and Brown -- and thus monstrous.