Looks windy too. I find myself looking for something more in 1, though the sky is lovely. I wonder if some PP on the beach might help? 2 and 3 are potentially really good, but let down by an uninteresting sky. Definitely worth pursuing. I think there is too much low, reflected light and inky shadow in 4 for it to work.
I have photomatix pro but find it difficult to use, probably because i hardly ever use it. Perhaps i should!!Maybe too far, and contrast and sharpening need looking at. I came up with something similar. I find that I am increasingly running a pseudo HDR across my pictures to see whare they CAN go, then looking to realise some of that potential conventionally. Pseudo HDR introduces a huge amount of noise and is inclined to be destructive. Do you have Photomatix or Dynamic Photo HDR?