looking at those motors the PF XL will be your best choice of motor, you will somehow need to achive about 250-300 rpm, possibly with the use of a gearbox, 300rpm is pretty quick, 5 revolutions per second.
also to consider is that when using a motor to create power, the load put on that motor acts like a brake, so you will also have to have a fair amount of torque there to drive it, the only way your going to get torque is with
A, Big blades
B, Lots of water
can you not use other ways to light these leds, like geothermal, wave power, solar, wind etc would be much easier to accomplish in my opinion