As for 2000, I still can't figure out how mathematically someone can get "over 80%" of the vote of the demographic group that has the majority population in a county, and win only 46% of the vote overall countywide. That doesn't make sense. I wish elections worked that way in my district and Bobby Rush would end up with 46% district wide while he's getting over 80% of the black vote.
Martinez and Bush helped each other win—Mel ensured a high Cuban turnout in Miami and a strong GOP performance among Hispanics in Central Florida (which helped Bush carry the Puerto Rican vote, which in turn helped him carry Osceola County), while Bush increased Evangelical turnout throughout the state and increased the Jewish Republican vote in the Gold Coast, thus helping Martinez. However, Bush ran far ahead of Martinez in old Dixiecrat counties as well as among “Old Florida” voters in the Tampa Bay area and Jacksonville. Had McCollum been the nominee, it is likely the Bush would have gotten clser to 50% than to 52%, and that Castor would have beaten McCotter.
As for your confusion with the math of the 2000 election in Miami-Dade, I’m reposting my explanation. In summary, the group that gave Bush around 83%-84% were Cubans in particular, not Hispanics in general, and Cubans were between 28%-30% of the Miami-Dade electorate. But read the whole thing:
According to the 2000 Census, 57.3% of Miami-Dade residents were Hispanic, and only 28.87% of Miami-Dade residents were Cuban. http://www.miamidade.gov/business/library/reports/data-flash-hispanics-origin.pdf
Given that many Hispanics, including many Cubans, are non-citizens, I would guesstimate that the percentage of Miami-Dade County voters in 2000 who were Hispanic was not much higher than 50%, and the percentage of voters there who were Cuban was around 30%. And since the county not only has a large black population, but also a very liberal white Anglo population (mostly Jewish, who voted overwhelmingly for Gore-Lieberman), I see nothing strange about Bush getting 84% of the Cuban vote while getting only 46% in the county.