It is possible, as I understand it, to detail strip. The FNP was designed to be a modular pistol. I don't know the procedure, but I assume there are people, that have been to an FN armorer school, who know how. The problem being that they are most likely military or LEOs, I am not sure that there is an armorer class which is available to the general public.
I detail strip everything but the slide (can't) and hammer assy (too hard, carb cleaner works fine). Once you take off the slide and all the junk out you can, pop out the slide stop. After that, wedge a screwdriver in the frame, bend it open, and pull out the locking block. After that pull out the front piece in a similar manner, and the slide rails pop out of the frame. From there you can push out the pin and remove the trigger.