anybody knows if apple headphones work fully with FP1?
Do you mean bluetooth headphones or wired ones?
You may need an OMTP to CTIA adapter if you want to use the microphone on wired Apple headphones (EarPods, not AirPods.) I suppose Bluetooth devices such as the AirPods will work in any case. For the Fairphone headphones, no adapter is required either.
preferably wired ones
Standard headphone jack is just analog. So the simple answer is: yes.
@teezeh yes, except that there are two standards to wire the microphone: https://en.wikipedia.org/wiki/Phone_connector_(audio)#TRRS_standards
I believe, but I am not sure, that the FP1 only supports OMTP, not CTIA. The FP2 and FP3 support both.
You can probably listen to music in any case, and if the microphone fails to work, you can get an adapter.
The question was about headphones, not headsets
Does Apple sell headphones without microphone? The OP asked whether Apple headphones work fully, so I assumed that a working microphone was implied.
And for me a headset is either a large one that goes over your head, or a thing you put in 1 ear to work in a callcenter.
I have been using the Sony MDR-EX15AP earphones with microphone on my own FP1U for a couple of years now and apart from hearing audio (which I would take for granted from any headphones with a 3.5 mm plug), the FP1U also accepts the input from the sole button the Sony MDR-EX15AP has – it works to accept a call and it works to pause and resume a song. Microphone input is also accepted (read: I can use it for phone calls).
However, button input only works in the default apps pre-installed on the FP1U. If I use the button while playing music with VLC, the button push will only launch the “Music” app (which is not what I’d want it to do). Sometimes I need to plug in the Sony MDR-EX15AP 2-3 times before the FP1U recognizes it (pure headphone icon vs. headset icon in the notification bar).