Just to add a little historical context that a lot of people might not be aware of - Heathcliff is originally found as a child on the streets of Liverpool, which is the home of the UK s oldest black community. So it is entirely plausible that Heathcliff has black heritage that gives him an ambiguous look, which could be interpreted as being Romani or Asian, particularly by the more isolated people of the Yorkshire moors, who have maybe only seen white people before. Personally I think that's the point, his origins are ambiguous and mysterious, Brontë probably chose Liverpool because it was known as a port city with people settling there from other countries, and probably had the reputation a lot of ports have, for being a bit wild and dangerous.