I use this library, but mainly for IEC corrected LED lighting. Driving PT4115 LED drivers (sink only).
There are also commands in that library to set the 12-bit PWM directly (never used that).
I think you can set PWM directly with most PCA9685 libraries.
The PCA is AFAIK in totempole output by default.
Not sure if you have to change that for n-channel mosfets.
Just try with one channel.
Leo..