Greg, where your paddling at it seems like you will be fighting the wind and a bit of current during tide changes. I've paddled around Fort Fisher a time or two and the salt marshes around Bear Island and several different lakes and it can be a lot of work in the wrong boat. Of course a long kayak is much easier to paddle and tracks staight in open water. Shorter kayaks is easier in tight places and easy to manuver. A flat, wide bottom is stabile but the wind will blow you around like a leaf, while a bottom with more of a V will cut the water making it easier to paddle and allow straight-line tracking. You need something in between. Don't get nothing less than 12ft long, longer is better. Don't get nothing to narrow or it may be tippy. A 12ft kayak is much more stable than a 12ft canoe(if their widths are similar) for the fact you are sitting on the floor of the of the kayak while your sitting close to 8in higher than that in the canoe. Go to some of the kayak rental/dealers ask questions and take them for a test drive. You might realize a kayak is a bit more stabile than you thought and those sit on top kayaks are tough to paddle far in the wind but they are very stabile, it just all depends on what you want but definately go to some of the kayak shops, get advice and test drive before spending your money.
Dave