Florida light is bright, warm, and relentless, and it reverses a lot of color decisions made under fluorescent tubes in a paint store. The cool grey that looked expensive on the chip reads blue by a south-facing window. The warm white looks yellow. The greige goes pink. None of this is the paint's fault — it's that every color is only ever the light that hits it.
The fix is boring and it works: get a sample of each finalist, paint a large patch on the actual wall, and look at it over a full day. Morning, midday, and under your lamps at night. A two-inch chip held against a wall tells you almost nothing; a two-foot patch tells you everything. Paint the patch on more than one wall in the room, because the wall facing the window and the wall opposite it will not look the same color.
Watch for what the room is already doing to the color. A big green yard outside a bright window throws green onto the wall facing it. Terracotta tile pushes everything warm. A pool reflects moving blue light onto the ceiling. These are all real and they're all stronger than people expect.
Sheen matters at least as much as color and gets much less attention. Flat and matte hide wall imperfections beautifully but are hard to clean. Eggshell and satin wipe down and are the sensible default for most living spaces, hallways, and kids' rooms. Semi-gloss belongs on trim, doors, and in bathrooms, where it stands up to moisture and scrubbing. A wall painted in the right color and the wrong sheen will still disappoint you.
One last practical note: look at the ceiling before you commit to a wall color. A ceiling that's gone dingy or yellow, or still has 1980s popcorn texture on it, will undercut any color you put beneath it. Often the cheapest way to make a room feel genuinely updated is to do the ceiling at the same time as the walls, while the furniture is already covered and the room is already masked.