If you like this concept, I'll be glad to enhance this concept. But if I've gone far from your expectation, please leave any comment and feedback. And I'll be glad to come up with another concept.
#5 Skeleton (or multiple skeletons) is a cool idea, and is fair game for all designers. Fits the brief. This one's too generic, however. Needs to identify with inshore fishing easily. Posture of the fish matters as well. This one looks like it's in pain. I think "FlatsClass" should be secondary to the art, or blended in. I want people to love the shirt first, then see who it's from.
These guys are also working on a design for us. If you do want to keep using the skeleton idea, it needs to be more realistic, less cartoonish. The really fat lips look more like a goldfish than a gamefish. #6 has a shot at being a cool women's shirt. Nice art!