Regarding the Mason-Dixon Line, it might still leave some room open for interpretation.
Regarding point b), this map might be relevant:
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Note that the "Y'ALL" line roughly coincides with the location of the original Mason-Dixon Line. Although it drops further to the south as it extends further west.
(On the other hand, they reduce "you all" to a one-syllable word, while "you guys" not only make it into two syllables, but two separate words. As for those who say "youse guys," well, that doesn't even make any sense.)
I live in a Republican state, although the county I live in is majority Democrat. We're probably more "purplish," one of the "swing states." Florida also has some blue and purple areas, too. I don't know of any state which is straight down the line one or the other.
But regarding the OP, Florida does seem to be one of those states which has always had a special kind of crazy. Even among Southern, conservative states, Florida seems to stand out as a kind of oddball.