I'll guess that you will get the usual answers... take classes, paddle as many boats as you can... and so on.

That's because the first boat that you buy will not be the "right one" for you

I'm on my second boat. I'm 5'6" @ 145 lb and ended up with an Eddyline Fathom LV. It was a very good fit and beautifully made. But last August I tried a RockPool Alaw Bach TCC (also made by Eddyline), which measures in a just over 17 feet. I couldn't believe the difference between the two kayaks. I traded for the RockPool. But others might have just the opposite reaction because fit and feel are so personal. And it was only after three summers that I had enough seat time to make that (for me) differentiation.

Anyhow on your present list I would lean for the Wilderness Systems Tempest 170 as it seems to offer more of a "real" sea kayak profile and will probably fit you better. The P&H Delphin might also be a good fit.

Hope you find the right boat.