A lot of kayak stores have beach days where they bring a bunch of models to a local put-in and let people try them out. I’d suggest going to one of those, if possible. I find that sit-on-top kayaks are uncomfortable and give me leg cramps, but lots of people like them. They’re probably intrinsically safer than sit-in kayaks because they’re essentially unsinkable and self-draining. The sit in kayaks are maybe faster and will keep you drier in rough conditions.
Long kayaks will be faster but more cumbersome to turn, especially if you’re exploring little inlets in marshes.
I haven’t tried any of the pedaling kayaks but they look like they’d be excellent for photography purposes. I like to use my sea kayak to try to creep up on various wildlife but it’s hard to be inconspicuous when you’re waving a paddle with two great big white blades on it. (On the other hand, if you’re kayaking in a busy waterway, you want the biggest most fluorescent blades you can find, just so that yahoos in powerboats can see you at a distance.)
Oh, consider weight as a factor as well. SUVs are the very devil to put kayaks on top of, and it’s not a lot of fun dragging a heavy kayak across the rocks at low tide. So lighter is better (but, alas, more expensive as well.)