Your assumptions are correct. You need to set up the PCA9685 driver. The default address should be 64 (0x40) unless you've bridged any of the address jumpers. Pretty much any frequency between 100 and 1500 should work just fine. You can use 1000, unless you have any other pwm devices you are planning to hook up.
I finally figured it out, woot! The moon lights are working, they are pretty bright but dim down really nice, now to add the other 2 channels for the main light.
Pretty stoked hopefully they work also!