Hopefully GrassGuy will see your question, as he is in FL also, and will have insights. My experience with Blue Fescue is they don't like heat and humidity at all. I have at least 50 plain old seed-grown plants, and those in full sun, where they do best in spring and fall, get ratty in the summer. I usually give them a close haircut when the plumes get to the point of seed ripening. That's usually late July for me, and they look like little brown hedgehogs until cool weather brings on new foliage.

I have no experience with the various cultivars yet.

Unfortunately, as donn suggested, blue fescue grasses melt in the humidity of fl summers. In the panhandle, they are typically goners by late June. I've managed to keep them year-round in heavy shade, but they look very bad and don't come back strong.

Same with the blue helictotrichon.

I'd suggest a blue leymus grass, agropyron, carex blue zinger, or even a blue juncus...if blue is what you're after.