Sounds like you are going to be mainly in backwaters, so as long as you are on the lee side of shores, wind should not be a major factor. I've been out in 20+ mph wind and if you are in open water you will get beat up and wet.

I usually wear my PFD in deep open water, but take it off in shallow water when I'm fishing. As mentioned before, the greatest danger in a kayak in saltwater is power boats. Never assume they see you and stay out of their way. In fact, I make it a practice to assume they are trying to hit me and act accordingly.